Using the SDL Editor

About Symbols and Lines

Following is a description of the components in the drawing area. See also Symbols and Lines -- Quick Reference.

The Additional Heading Symbol

Symbol Appearance	Symbol Name	References to Z.100
	Additional heading	Z100: 2.2.5 Additional heading Z100: 6.1.1.3 Process type heading Z100: 2.4.4 Formal parameters, Signalset Z100: 6.3 Specialization Z100: 6.3.1 Inherits Z100: 6.3.2 Virtual, Redefined, Finalized Z100: 6.3.2 Virtuality constraint (atleast) Z100: 6.2 Actual context parameters Z100: 6.2 Formal context parameters Z100: 6.2.1 - 6.2.9 Formal context para

The additional heading symbol is not defined further according to Z.100. In the SDL Editor, it looks like a dashed text symbol or it is shown without any border; this is controlled by the Editor preference ScreenZ100Symbols. The symbol is editable and resizeable, but cannot be moved. Its intended use in SDT is to define:

• Inheritance and specialization, using the following keywords:
• INHERITS
• ADDING
• ATLEAST
• Formal parameters for a process / procedure, using the keyword FPAR
• Directives to the C Code Generator. A C Code Generator directive uses the SDL comment notation and a hash character, such as:
  /#INCLUDE file.pr */
• SIGNALSET and instance information.

The additional heading symbol is repeated through all pages contained in an SDL diagram.

Note that the combined text in the Kernel Heading and the Additional Heading symbol must use the syntax as specified for a heading in SDL-PR to be accepted in the SDT Analyzer.

The Package Reference Symbol

Symbol Appearance	Symbol Name	References to Z.100
	Package reference	Z100: 2.4.1.2 Reference in Package Z100: 2.4.2 Reference in System

The package reference symbol is available on system and package diagrams only. It is located outside the frame, on top and to its left. It contains references to package(s) containing definitions that are to be included in the SDL system.

You can select and resize, but not move the package reference symbol.

Other SDL Symbols

These are the symbols that describe the structure or behavior of the SDL diagram. They must be placed inside the frame.

You can draw symbols in color, see Color on Symbols.

Syntax Checking on Symbols

The SDL Editor checks that the symbols you add to a diagram are in accordance with the syntactic rules imposed by SDL. Symbols that are not allowed in a diagram / page of a specific type are dimmed in the symbol menu. Also the text entered is checked for syntax errors. See Syntax check.

Symbols on Interaction Pages

Symbol Appearance	Symbol Name	References to Z.100
	Text	Z100: 2.5.4 Signal Z100: 2.5.5 Signal list Z100: 5.2.1 Newtype Z100: 5.3.1.9 Syntype Z100: 5.3.1.13 Synonym Z100: 5.3.1.12.1 Generator Z100: 4.13 Remote variable Z100: 4.14 Remote procedure
	Comment	Z100: 2.2.6
	Text extension	Z100: 2.2.7 (depends on the symbol connected to)
	Block reference	Z100: 2.4.2 Block definition Z100: 6.1.3.2 Block def based on block type Z100: 6.1.2 Type expression Z100: 6.2 Actual context parameters
	Process reference	Z100: 2.4.3 Process definition Z100: 2.4.4 Number of instances Z100: 6.1.3.3 Process def based on block type Z100: 6.1.2 Type expression Z100: 6.2 Actual context parameters
	Block substructure reference	Z100: 3.2.2
	Service reference	Z100: 2.4.4
	System type	Z100: 6.1.1.1
	Block type	Z100: 6.1.1.2
	Process type	Z100: 6.1.1.3
	Service type	Z100: 6.1.1.4
	Operator reference (an SDL-GR extension defined in SDT)	Z100: 5.3.2 Referenced operator in SDL-PR
	Gate	Z100: 6.1.4 Gate Z100: 2.5.5 Signal list

Symbols on Flow Pages

Symbol Appearance	Symbol Name	References to Z.100
	State or nextstate	Z100: 2.6.3 State Z100: 4.4 Asterisk state Z100: 4.5 Multiple appearence of state Z100: 2.6.8.2.1 Nextstate Z100: 4.9 Dash nextstate
	Text	Z100: 2.5.4 Signal Z100: 2.5.5 Signal list Z100: 5.2.1 Newtype Z100: 5.3.1.9 Syntype Z100: 5.3.1.13 Synonym Z100: 5.3.1.12.1 Generator Z100: 2.6.1.1 Variable Z100: 2.6.1.2 View Z100: 2.8 Timer Z100: 4.13 Remote variable Z100: 4.13 Imported variable Z100: 4.14 Remote procedure Z100: 4.14 Imported procedure
	Input	Z100: 2.6.4 Input Z100: 4.6 Asterisk input Z100: 4.14 Remote procedure input Z100: 6.3.3 Virtual transition z100: 5.4.3 Variable z100: 5.4.3.1 Indexed variable z100: 5.4.3.2 Field Variable
	Comment	Z100: 2.2.6
	Save	Z100: 2.6.5 Save Z100: 4.7 Asterisk save Z100: 6.3.3 Virtual save
	Text extension	Z100: 2.2.7 (depends on the symbol connected to)
	Output	Z100: 2.7.4
	Decision	Z100: 2.7.5 Decision Z100: 5.3.1.9.1 Range condition Z100: 2.2.3 Informal text
	In-connector or out-connector	Z100: 2.6.7 In-connector Z100: 2.6.8.2.2 Out-connector
	Task, set, reset or export	Z100: 2.7.1 Task Z100: 5.4.3 Assignment Z100: 2.8 Set, Reset Z100: 4.13 Export
	Procedure call	Z100: 2.7.3 Call Z100: 2.7.2 Actual parameters
	Macro call	Z100: 4.2.3
	Create request	Z100: 2.7.2
	Transition option	Z100: 4.3.4 Transition option Z100: 5.3.1.9.1 Range condition
	Continuous signal or enabling condition	Z100: 4.11 Continuous signal Z100: 4.12 Enabling condition
	Start	Z100: 2.6.2 Start Z100: 6.3.3 Virtual transition
	Priority input	Z100: 4.10 Priority input Z100: 2.6.4 Stimulus Z100: 6.3.3 Virtual transition z100: 5.4.3 Variable z100: 5.4.3.1 Indexed variable z100: 5.4.3.2 Field variable
	Stop	Z100: 2.5.8.2.3
	Procedure start	Z100: 2.4.6
	Inlet	Z100: 4.2.2
	Return	Z100: 2.6.8.2.8
	Outlet	Z100: 4.2.2
	Procedure reference	Z100: 2.4.6 Procedure definition
	Operator reference (an SDL-GR extension defined in SDT)	Z100: 5.3.2 Referenced operator in SDL-PR
	Gate	Z100: 6.1.4 Gate Z100: 2.5.5 Signal list

Note:  The operator reference symbol is not part of the current Z.100 recommendation. It has been added to the SDL Editor as a convenience for the SDT user. It makes operators visible in the SDL structure which is handled by the Organizer and facilitates thus navigating. The operator reference symbol does not, however, refer to the operator diagram implicitly. References to operator diagrams must be explicitly entered in SDL-PR, as stated in Z.100.

Graphical Properties of Symbols

You can select and move all symbols that are available in the symbol menu, and you can assign the symbols arbitrary locations.

You can resize certain symbols; these are indicated by filled selection squares. Other symbols can only be partially resized or cannot be resized at all¹; this is shown by grayed selection squares.

Figure 353  : Resizeable and non-resizeable symbol

No symbol is allowed to overlap any other symbol except the text symbol and the additional heading symbol.

Text / Additional Heading / Package Reference Symbols

The text, additional heading and package reference symbols look like a piece of paper. When all of the text within a text symbol is in view, the upper right corner is "folded" down. When any portion of the text within a text symbol cannot be seen (because the text symbol is too small), the upper right corner is clipped or diagonally cut off. See Figure 353.

Clipped text symbols are printed in their whole on a separate sheet of paper.

Comment / Text Extension Symbols

The comment and text extension symbols can be shown either in full size enclosing the complete text or clipped (collapsed) where the symbol is in the minimum size and only the first part of the text is visible. The clipped symbol is visualized as if the lower right corner has been cut off. See Figure 353.

Block Substructure Symbol

The appearance of this symbol differ from the drawing rules in Z.100. The non editable text "substructure" is drawn inside the symbol. Without this extra text it is impossible to distinguish the block symbol and the block substructure symbol by their visual appearance.

The appearance can be set to be according to Z.100 by the Editor preferences ScreenZ100Symbols and PrintZ100Symbols. Setting these to on means that the extra text will not be drawn or printed.

Symbol Text Attributes

Most SDL symbols have one or multiple text attributes. A text attribute should be filled with an SDL-PR expression (textual expression) that is syntactically correct according to Z.100. Depending on the correctness of the text, the SDT tool set has the ability to perform the following operations:

• Syntactic Analysis
• Semantic Analysis
• Pretty-printing
• Generation of reports
• Generation of code.

Syntax Checking on Text Attributes

You are not forced by the SDL Editor to fill text attributes with text. However, a context sensitive syntax check is performed for each text attribute. The first located syntax error is indicated by a red bar underlining the text where the error occurs.

A global syntax check for the complete diagram is performed by the SDT Analyzer.

Reference Symbols

Diagram reference symbols allow to build an entire SDL system by referring to diagrams that are structurally related. Reference symbols are the following:

• Block reference
• Process reference
• Block substructure reference
• Service reference
• System type
• Block type
• Process type
• Service type
• Operator reference
• Procedure reference.

These symbols are handled by the SDL Editor in order to ensure consistency between the SDL diagrams and the SDL structure that is handled by the Organizer. Because of that, the SDL Editor imposes the restriction that a reference symbol must be unique within an SDL diagram (this restriction is not in conflict with Z.100).

You are permitted to have diagram reference symbols that are not assigned any name.

The SDL Editor performs a number of checks when you edit an SDL reference symbol. Furthermore, when you double-click a reference symbol, the SDL diagram that the symbol refers to will be opened.

See also Working with Diagram Reference Symbols.

Instantiation Symbols

You may use any of the following reference symbols for the instantiation of a type:

• Block reference
• Process reference
• Service reference.

An instantiation symbol differs from a "normal" reference symbol in the sense that the syntax of the symbol's text differs. The syntax is:

a:a_type

where a_type is the name of the SDL type diagram (block type, process type or service type diagram) that is instantiated into the diagram with the name a.

Instantiation symbols are visualized in the Organizer structure. The Organizer structure is updated to reflect the nature of the changes applied to the SDL diagram, in a similar fashion as for diagram reference symbols (see Reference Symbols).

The names of instantiation symbols must be unique within an SDL diagram.

See also Working with Diagram Instantiation Symbols.

Dashed Reference Symbols

Any of the following reference symbols may be dashed:

• Block reference
• Process reference
• Service reference.

Dashed symbols are visualized in the Organizer structure. The Organizer structure is updated to reflect the nature of the changes applied to the SDL diagram, in a similar fashion as for diagram reference symbols (see Reference Symbols).

The names of dashed reference symbols must be unique within an SDL diagram.

See also Working with Dashed Symbols.

Lines

Lines are the graphical objects that interconnect symbols. One line only is available in the symbol box, namely the gate, which is handled as a symbol. You can insert it by selecting it and placing it into the drawing area.

You insert the other lines by selecting a symbol and dragging the handle that appears on the source symbol and connecting it to the target symbol. (Some symbols have multiple handles).

Lines are always connected to symbols, they are not allowed to exist on their own.

Figure 354  : A handle

You can select, move and reshape lines. Some layout work is performed automatically by the SDL Editor.

A line is allowed to overlap any other object.

Lines in Interaction Diagrams

Figure 355  : Lines (1)

Figure 356  : Lines (2)

The following lines are defined in interaction diagrams (see Figure 355 and Figure 356):

• channels
• channel substructures
• signal routes
• create requests
• text extension lines
• comment lines

You can reshape each of these lines and you can also move the connection points.

Lines in Flow Diagrams

Figure 357  : Lines (3)

On flow diagrams, the following lines are defined (see Figure 357):

• flow lines
• comment lines
• text extension lines

Line segments on flow pages always use a 90-degree angle. You can add segments on a line, but connection points are fixed.

Syntax Checking on Lines

The SDL Editor checks that the target symbol is in accordance with the syntactic rules imposed by SDL. If not, the SDL Editor will refuse to connect the symbol. When you edit the text attributes are instantly checked for syntactical errors.

Textual Objects

Textual objects are the textual attributes that are related to a symbol or a line. Each of these attributes is prepared by the SDL Editor -- you need of course to fill in their textual contents.

Textual attributes are indicated by a small rectangle which appears upon selection of the symbol or line the attribute belongs to.

You can select and edit textual objects. You can move them freely, as long as their location does not violate the rules defined by Z.100.

Textual objects are allowed to overlap any other objects.

Textual Objects in Interaction Diagrams

The following textual objects are defined in interaction diagrams:

Graphical Appearance	Textual objects
	Name of a diagram reference symbol Includes the number of instances for a process reference symbol
	Name of a diagram type reference symbol
	Name of a diagram instantiation symbol (e.g. inst:blk_type) Names of graphical connection points in diagram instantiation symbol (e.g. CON1)
	Name of a channel or signal route (e.g. CH) Signal list on a channel / signal route (there are 2 signal lists if the line is bidirectional, e.g. Sig1 and (Siglist)) Connection point for channel / signal route to / from environment, e.g. CON
	Name of a gate, e.g. GA Signal lists on a gate (there are 2 signal lists when the gate is bidirectional, e.g. Sig1 and Sig2)

Textual Objects in Flow Diagrams

In flow pages, the following textual attributes are defined:

Graphical Appearance	Textual objects
	Decision expressions connected to a decision symbol or transition option, e.g. Expr1 and Expr2.
	Name of a gate, e.g. GA Signal lists on a gate (there are 2 signal lists when the gate is bidirectional, e.g. Sig1 and Sig2

Graphical Connection Points

Connection points are text objects which are created automatically by the SDL Editor when you draw a channel or signal route to the frame or to an instantiation symbol.

They are handled in a similar way as other text attributes. You are free to fill connection points on the frame or not. The alternative is to define textual connection statements between channels and signal routes in a text symbol.

Change Bars

A change bar is a vertical line to the left of a text in an SDL diagram. It visually identifies changes in the SDL system.

A solid change bar indicates that the text has been changed. A dotted change bar indicates that a text or its associated symbol has been moved.

The change bars associated with the diagram name and the page name act as change bars for the complete page. As soon as a change has been made to a page, change bars for the diagram name and the page name are added.

You can turn change bars on and off and also clear them from the Organizer. See Change Bars.

Working with Symbols

The main operations provided by the SDL Editor on symbols is described in this section.

• Working with Diagram Reference Symbols
• Working with Diagram Instantiation Symbols
• Working with Dashed Symbols
• Selecting Symbols
• Adding Symbols
• Inserting a Symbol into a Flow Branch
• Navigating in Flow Diagrams
• Navigating from Symbols
• Cutting, Copying and Pasting Symbols
• Moving Symbols
• Resizing Symbols
• Mirror Flipping Symbols
• Adjusting Symbols to the Grid
• Editing the Diagram Kernel Heading.

In addition, text editing functions are provided for the text associated with the symbols.

Working with Diagram Reference Symbols

When you perform certain modifications to the diagram reference symbols listed in the left margin (system type, block, block type, substructure, service, service type, process, process type, and procedure reference symbols), the SDL Editor checks with the Organizer to verify that the modifications are valid. This occurs in the following situations:

• Adding a Diagram Reference Symbol
• Adding an Operator Diagram Reference Symbol
• Renaming a Diagram Reference Symbol
• Removing Symbols

Working with Diagram Instantiation Symbols

Instantiating a Diagram Type

The implication of an instantiation symbol is that the description of the type diagram is actually instantiated, i.e. a physical copy is created. This copy may then be given additional properties using SDL's inheritance and specialization mechanisms.

When a diagram type is to be instantiated, do as follows:

1. Make sure the type diagram is visible according to the SDL scope rules.
2. Insert a diagram reference symbol. When specifying the name of the symbol, use the syntax <instance_name>:<type_name>.
3. When the symbol is deselected, thediagram structure is immediately updated to show the instantiation (this is only true if the Instance Diagram option is on in the Organizer's View Options).

Working with Dashed Symbols

Dashing and Undashing a Reference Symbol

Dashed reference symbols are used to refer to an object that is defined elsewhere in one of the supertypes of the current subtype.

To dash a reference symbol:

1. Select the reference symbol.
2. Select Dash from the Edit menu.

Selecting Symbols

With the SDL Editor, you often perform actions that apply on a selection. This section discusses topics related to selection of symbols.

Selecting a Flow of Symbols

You often want to select a flow of subsequent symbols in a flow page, including all branches - the tail of the flow. To select a flow of symbols:

1. Click on the symbol where the flow starts.
2. Select Select Tail from the Edit menu. The tail of the flow is selected. See Figure 358, where the left picture shows only one selected object and its associated connections, whereas the right picture shows the selected symbol and its connections plus the selected rest of the flow diagram -- the Selected Tail.

Figure 358  : Selecting the tail of a subtree

Selecting a Symbol That Has Associated Objects

Consider the following when you select a symbol which has lines or text associated with it:

• When you select a symbol, you implicitly select the associated objects as well. A text cursor is inserted directly in the text associated with a symbol, and the text window will be updated to contain the text.
• If you point to a line associated with a symbol, you will select the line, not the symbol. The process of selecting lines is described in Selecting Lines.
• If you point to the text associated with a symbol, the resulting selection depends upon the type of the symbol.

Displaying Selected Symbol Attributes

Selected symbol attributes are displayed as follows:

• When you select a symbol from which you can draw lines, it is displayed with a handle which you use when drawing lines from that symbol. Handles are shown in Figure 359.

Figure 359  : A selected symbol's handles

• The text attributes associated with a selected symbol is marked by drawing a rectangle around the text, as shown in Figure 360.

Figure 360  : A selected symbol's text attributes

• In an interaction page, a line is marked by drawing filled selection squares at the line's starting point, ending point, and each breakpoint. In the middle of each line segment is a tiny selection square that provides an easy way to create new breakpoints. See Figure 361.

Figure 361  : The selection squares of a line in interaction pages

• In a flow page, a selected flow line is marked by drawing filled selection squares in the middle of each line segment. This indicates that you can move the individual line segments (but not the flow line as a whole). See Figure 362.

Figure 362  : The selection squares of a line in flow pages

Adding Symbols

You may place symbols into the drawing area in either manual mode or in automatic mode.

Adding Symbols in Manual Mode

This section describes how to do this in manual mode. The automatic mode is described in Adding Symbols in Automatic Mode.

Selecting and Placing a Symbol

1. Click the symbok in the symbol menu.
2. Click at the desired location in the drawing area. Overlap of symbols is not allowed.

The symbol is drawn and adjusted to the symbol grid.

Entering Symbol Text Attributes

Once a symbol has been added, you can enter the text into the symbol's text attributes. The symbol remains selected. Enter the text required directly using the keyboard or edit the text inside the text window.

Connecting the Symbol to Another Symbol

Once the symbol is at the desired location it can be connected to another symbol as required.

To connect two symbols:

Note:  The line will be drawn only when the SDL syntax rules allow the symbols to be interconnected.

1. Add the source symbol, i.e. the symbol from where you want to draw the line.
2. Point the mouse onto the handle of the source symbol, and start dragging the handle. As soon as mouse motion has begun, you can release the mouse button. Point to the target symbol and click the mouse button. The line is drawn to the symbol and required text attributes are added to the connecting line. The box without brackets is reserved for the name of the channel, while the box with brackets [ ] is for the signal list.

Figure 363 : Having connected two symbols

3. Fill in the text attributes.

Conversely, once you have placed a symbol in the drawing area, you can follow the same procedure from a symbol resident in the drawing area to the new symbol.

Connecting the Symbol to the Environment

1. Hold the mouse pointer on the handle of the symbol, drag it to the frame (environment) and release the mouse button.
2. Enter text in the channel or signal route and connection point boxes.

Figure 364 : Having connected the symbol to the environment

Adding Symbols in Automatic Mode

The automatic mode is particularly useful when you want to add symbols sequentially or in parallel in a symbol flow. Both situations are described below.

Adding in Sequence

To add symbols sequentially within a flow page, proceed as follows:

1. Select the source symbol in the drawing area.
2. Double-click the target symbol in the symbol menu.

The target symbol is added to the source symbol, and a flow line is drawn between the two symbols if the syntax rules allow it.

3. Fill in the text in the target symbol.

The target symbol is positioned directly beneath the source symbol if possible. Otherwise, the added symbol is placed in the first available location to the right.

After this operation, the target symbol is automatically selected and the source symbol is de-selected.

Figure 365 : Adding in sequence

Adding in Parallel

To add symbols in parallel in a flow page:

1. Select the source symbol in the drawing area.
2. Press <Shift> and double-click the target symbol in the symbol menu.

The target symbol is added to the selected symbol. The source symbol remains selected.

You can repeat this procedure in order to add additional symbols to the selected symbol. The target is positioned immediately below the source symbol, if possible. Otherwise, the target symbol is placed in the first available location to the right.

Figure 366 : Adding in parallel

Using Default Placement

You can also take advantage of the auto-placement by double-clicking a symbol without having to connect it to other symbols.

Insufficient Space Left

When you insert a symbol using the double-click facility, there may not be any space left to perform the operation, The SDL Editor informs you of this with a message.

You have the following options:

• Click OK to increase the page. The Drawing Size dialog will be opened, where you can specify the new size of the SDL Page.

If you select this method, the SDL page may not fit any longer into the paper that you have set up with the Print preferences. The result may be an SDL page that requires multiple sheets of paper when printing it (unless you rescale it).

• To Cancel the operation. Try to find a more suitable location for the new symbol and use manual placement (see Adding Symbols in Manual Mode).

Adding a Gate Symbol

The gate symbol differs slightly from other symbols when you add it.

Adding a Gate in Manual Mode

1. Select the gate symbol.
2. Move the pointer into the drawing area. The gate is immediately displayed and connected in a 90-degree angle to the frame and the environment.
3. Move the mouse to a suitable location. The gate symbol follows the mouse motion and is automatically reconnected.
4. Click the mouse.
5. Enter the name of the gate and the signals it conveys.

Note:  Coalesced Gates and Connection Points See Connecting a Gate Symbol with a Channel or Signal Route if you get a message with the text "A Gate has coalesced with a connection point...".

Adding a Gate in Automatic Mode

You may add and connect a gate to a channel or signal route with a double-click. The channel or signal route must not be already connected to a gate or connection point.

1. Select the channel or the signal route.
2. Double-click the gate symbol in the symbol menu.
3. If required, redirect or bidirect the gate so that it matches the direction of the channel or signal route.
4. Enter the name of the gate and the signals it conveys.

Adding a Diagram Reference Symbol

When you add a diagram reference symbol, the SDL Editor checks that the name and type are unique within the SDL diagram. The SDL Editor will refuse any duplicates. The newly added reference symbol is then inserted into the Organizer's diagram structure.

1. Select the symbol to be added from the symbol menu and add it to the diagram.
2. Type in the name of the symbol.
3. Deselect the symbol. The SDL Editor checks that the name and type are unique within the SDL diagram being edited.

If the new reference symbol is accepted, it is inserted into the SDT diagram structure, located beneath the referring diagram.

Adding an Operator Diagram Reference Symbol

In a data type construct it can be stated that an operator diagram is referenced elsewhere. This means that the operator will not be described in the current place, but in an operator diagram.

The SDL Editor does not know that the operator is referenced in a data type. The operator reference symbol is available for this situation. It is a convenience that has been added to the SDT tool set to facilitate navigating within an SDL system. Its presence in an SDL diagram does not modify the meaning of the diagram.

You add an operator reference symbol in a similar manner as when adding any other reference symbol. See Adding a Diagram Reference Symbol.

Inserting a Symbol into a Flow Branch

The SDL Editor allows you to insert symbols into a flow branch. When inserting symbols, the SDL Editor will rearrange the page in order to prepare the required space for inserting the symbol. This can be done in different ways:

• By pushing the tail of the branch downwards. This is the preferred method.
• By increasing the size of the SDL page.

Inserting a Symbol into a Flow Branch

1. Select the symbol in the symbol menu.
2. Point to the line interconnecting the symbols where the new symbol is to be inserted.
3. Click the mouse.

Figure 367 : Inserting a symbol into a flow branch

Inserting a Symbol by Double-Click

To insert a symbol into a flow branch by double-clicking it:

1. Select the line that interconnects the two symbols. Alternatively you can select the symbol preceding the line, see Insert Paste.
2. In the symbol menu, double-click the symbol to be inserted.

Figure 368 : Inserting a symbol with double-click

Navigating in Flow Diagrams

For certain symbols you can use the Navigate command in the Tools menu or double click on the symbol to navigate around in the diagrams. These symbols are:

• Create request, procedure call and macro call
• State and nextstate
• Inconnector and outconnector
• Reference symbols; see further Navigating from a Diagram Reference Symbol

Navigating from Create Request and Procedure/Macro Call

For a create request, procedure call or macro call the Navigate command will show the corresponding process, procedure or macro diagram. The diagram is found by searching in the Organizer structure for all relevant diagram types matching the name used in the symbol. If one and only one match is found this diagram will be shown in the editor. If there exists more than one diagram a dialog is issued.

Navigate to the desired diagram by selecting it in the dialog.

Navigating from State/Nextstate

For a state or nextstate the Navigate command will show other occurrences of the same name(s) in other state or nextstate symbols within the same diagram. If only one symbol matches the name search this symbol will be shown. If more than one symbol have the same name, a dialog is shown.

Navigating from Connectors

For an outconnector, the Navigate command will show the corresponding inconnector in the same diagram having the same name as the outconnector.

Similarly for an inconnector; you can navigate to all occurrences of outconnectors within the same diagram having the same name as the inconnector.

Navigating from Symbols

Navigating from a Diagram Reference Symbol

When you double-click or choose the Navigate command on a diagram reference symbol, the SDL diagram that the reference symbol refers to is opened, provided that the diagram is included in the Organizer structure.

This feature allows easy navigation down an SDL hierarchy.

See also Navigating from an Instantiation Symbol and Navigating from a Dashed Symbol.

Navigating from an Instantiation Symbol

You may use instantiation symbols to navigate in the diagram structure.

When you choose Navigate in the Tools menu or double-click on an instantiation symbol, the SDL Editor matches the name of the type referred to in the instantiation symbol against the existing type diagrams in the Organizer structure. The following happens depending on how many type diagrams that match the given diagram name.

• One and only one diagram is found: This diagram will be shown.
• No diagram matches the name: A dialog will appear which offers the possibility to open the Type Viewer window which can be used to navigate among the inheritance and redefinition trees extracted from the SDL system:
• More than one diagram is found: A dialog will appear showing the file names of all the found diagrams. Additionally the possibility to show the Type Viewer window is available.

Navigating from a Dashed Symbol

When you select Navigate in the Tools menu or double-click a dashed symbol, a scenario similar to the action of navigating from an instantiation symbol takes place. See Navigating from an Instantiation Symbol

Cutting, Copying and Pasting Symbols

The clipboard of the SDL Editor allows you to cut or copy a selection of symbols. The selection may then be pasted to:

• The same page
• Pages of the same diagram, provided the page types match
• Other diagrams, provided the diagram types match

See also Cutting, Copying and Pasting Reference Symbols.

Cutting and Pasting Symbol(s)

A dialog may appear when cutting or pasting an object with link endpoints. See Deleting an Object or Pasting an Object.

Limitations when Pasting

Note:  Effect of Syntax Check when Pasting Some symbols may not be pasted if the syntax check is on. The clipboard buffer content must comply with the SDL syntax rules. Any symbols which do not comply will be omitted. (The clipboard buffer content may have been copied from a page edited with syntax checking turned off.)

Pasting is not always possible. Note the following cases, and refer to Relationship between Diagrams and Pages.

• The selection cannot be pasted if the page is too small. In this case, you need to enlarge the page. See Resizing a Page.
• You are not allowed to paste symbols so that they overlap existing symbols in the drawing area. If you attempt to do this, the Paste operation is cancelled. Try another suitable location.
• You are not allowed to paste flow symbols into an interaction page and vice versa. In this situation, the Paste menu choice is dimmed.

Pasting on Flow Pages

On a flow page, symbols are pasted along with the flow lines that interconnect them.

Pasting on Interaction Pages

On an interaction page, symbols are pasted along with the lines that interconnect them. Any lines that connect the pasted symbols to the environment will also be drawn.

Pasting Symbols into a Flow Branch

On a flow page, symbols can be pasted into a flow branch in a similar manner as Inserting a Symbol into a Flow Branch.

1. Copy or Cut one or more symbols in a flow page. The symbols must be connected and placed below each other.
2. Go to the page where you want to insert the symbols and select a symbol or a flowline.
3. Select Insert Paste from the Edit menu.
4. The pasted symbols will be placed below the selected symbol and inserted into the flow branch. Any previously following symbols will be automatically shifted downwards to make place for the inserted symbols.

Cutting, Copying and Pasting Reference Symbols

When you cut or copy a reference symbol, the possible sub-hierarchy shown in the Organizer below this reference symbol is also placed in the clipboard. When pasted in the same diagram or in another diagram this sub-hierarchy will be restored at the new position.

Note:  When a reference symbol is cut, the sub-hierarchy that is shown in the Organizer will be removed. However, the hierarchy will be restored if you select Paste or Undo.

When you copy or paste a diagram reference, it is assigned a new name that consists of the original name, preceded with the prefix CopyOf. The prefix is repeated as many times as necessary in order to build a name / type combination that is unique within the SDL diagram being edited. If the cut/copied symbol had an underlying structure this structure is restored after the paste.

Moving Symbols

You may move one or more symbols in a single operation. The lines and text objects that are related to the symbol will be moved accordingly in order to preserve as much as possible of the original appearance. When you move a symbol, its position is automatically adjusted to fit exactly into the symbol grid.

Symbols are not allowed to be moved to positions where they would overlap other symbols.

Moving Symbols and Text Attributes

You can move symbols and text attributes by pointing and dragging to the desired position.

You cannot move text in flow symbols.

Connecting a Gate Symbol with a Channel or Signal Route

When you move a gate symbol in order to reconnect it to a line or vice versa (channel or signal route that is connected to a connection point), the following takes place:

• If the connection point is not assigned any name, the SDL Editor connects the gate symbol and the line.
• If the connection point is assigned a name, a conflict occurs, since the line cannot be connected to the connection point and the gate simultaneously. The following dialog is issued:

Figure 369 : Prompting to solve connection conflict

You have the following options:

• To keep the gate G1 and to connect the line to it. The connection point Conn is removed.
• To keep the connection point Conn and to connect the line to it. The gate G1 is removed.
• Click OK to reconnect the line and symbol accordingly.

Note:  The situation above also occurs if you add a new gate symbol and place it on a connection point.

Moving a Symbol That Is Connected to the Frame

When you move a symbol which has a line connected to the frame, you can specify whether to move the connection point or not.

1. Select Diagram Options from the View menu. A dialog is issued.
2. Turn the Endpoints fixed at frame toggle button on or off, depending on your preference.

Figure 370  : The effect of fixing endpoints at frame

Resizing Symbols

The procedure for resizing a symbol differs slightly depending on whether the symbol is a flow page symbol or an interaction page symbol. When you resize a symbol, its size is automatically adjusted to fit exactly into the symbol grid. Any lines connected to the symbol are similarly adjusted to preserve as much as possible of the original appearance.

The text, the additional heading, the package reference, comment and text extension symbols are handled differently. Their sizes are determined by the SDL Editor to fit the text they contain.

Specifying Default Size of Symbols

You define the default sizes for symbols in the Preference Manager:

• For interaction pages, the predefined size of a symbol is 30 * 20 mm.
• For flow pages, the predefined size of a symbol is 20 * 10 mm. The width / size relationship is always 2:1.

Resizing Interaction Page Symbols

1. Point to a corner of the rectangle that delimits the symbol. From this point on, the corner that you are pointing to is movable, while the opposite corner is fixed.
2. Drag the corner until the symbol has the desired size. An interaction symbol cannot be adjusted to a size less than 15*10 mm.
3. Release the mouse button. The symbol is redrawn with its size adjusted to fit exactly into the symbol grid. The lines connected to a resized interaction symbol are automatically adjusted to preserve a nice appearance.

Resizing Flow Page Symbols.

1. Point to a corner of the rectangle that delimits the symbol. From this point on, if you pointed to any of the lower corners, the top of the symbol is fixed (and in a similar way, if you were pointing to any of the upper corners, the bottom of the symbol is fixed).
2. Drag the corner until the symbol has the desired size. The symbol shrinks or swells both horizontally and vertically, the proportions remaining 2:1. A flow page symbol cannot be adjusted to a size less than 20*10 mm.
3. Release the mouse button. The symbol is redrawn.

Resizing Text / Additional Heading / Package Reference /
Comment / Text extension Symbols

The text, additional heading and package reference symbol look like a piece of paper. When all of the text within a text symbol is in view, the upper right corner is "folded" down. When any portion of the text within a text symbol cannot be seen (because the text symbol is too small), the upper right corner is clipped or diagonally cut off. See Figure 371.

Clipped text symbols are printed in their whole on a separate sheet of paper.

These symbols react in the same way for resizing. There are several ways you can resize these symbols:

Adjusting to a Specific Size
(only for Text / Additional Heading / Package Reference)

1. Place the mouse pointer on the filled selection square at the bottom right corner of the symbol.
2. Holding the left mouse button down, make the symbol smaller by pushing to the left or larger by pulling the corner to the right.

Toggling Between Minimum and Maximum Size

You may rapidly toggle between a text symbol's maximum and minimum size. This can be accomplished in two ways:

• Select the symbol and choose the Collapse/Expand command in the Edit menu.
• Double-click on any part of the symbol.

Figure 371  : Minimizing and maximizing a symbol

Mirror Flipping Symbols

The input, priority input, output, comment and text extension symbols are drawn by default as displayed in the symbol menu. In some cases, the layout of the connecting lines would be nicer if the symbols were drawn flipped L/R.

1. Select the symbol.
2. Choose Flip from the Edit menu. The symbol is flipped L/R.

Figure 372 : Flipping a symbol

Note:  By using the Preference Manager you can specify whether the output symbol in the symbol menu should point to the left or to the right, or you can have both. The same applies for the input and priority input symbols.

Adjusting Symbols to the Grid

The drawing area of the SDL Editor provides two grids for easier positioning of objects. These are the symbol grid and the line grid, which are invisible.

After you move or resize symbols, the position of the upper left corner of each symbol is positioned on the closest intersection in the symbol grid. In addition, resizing a symbol will adjust the size so that it matches the resolution of the grid, horizontally as well as vertically. The resolution of the symbol grid is variable and can be set with the Preference Manager. The default is 5 * 5 mm for interaction pages, and 25 mm * 15 mm for flow pages.

You can temporarily disable the grid by toggling the Use Grid to off in the Diagrams Options dialog.

Handling Symbols of Different Sizes

Since symbols adhere to the symbol grid, mixing symbols of different sizes may imply that symbols cannot be aligned symmetrically, and that enlarging symbols becomes impossible due to overlap of symbols already laid out.

You can align symbols of different sizes by disabling the symbol grid.

Editing the Diagram Kernel Heading

You can rename, retype and re-qualify a diagram with the SDL Editor, by modifying the diagram's kernel heading.

Figure 373 : The kernel heading

See also Transforming the Type of a Diagram for more complicated transformation of diagram types.

SDT accepts a number of syntaxes for kernel headings, 13 in all. See The Kernel Heading.

Note:  Changing the kernel heading of a diagram may have a large impact on the diagram's meaning. Also, the SDL diagram structure where the diagram is included may be affected to a large extent. You may, however, want to change the kernel heading in order to create a new diagram that you will use in a different context than the SDL structure it originally is tied to, or in order to perform a simple rename of diagrams.

Changing the Name of a Diagram

This is the bottom-up method you would use when renaming diagrams in an SDL structure.

1. Select the kernel heading.
2. In the text window, edit the kernel heading text.
3. Deselect the kernel heading. The SDL Editor checks that the name is still valid according to SDL rules. Any syntax error will cause a dialog with the following alternatives to be issued:
• Clicking OK, you are returned to the text window where you should correct the error.
• Clicking Revert, the kernel heading is reverted to its original contents.
• Clicking Ignore, the erroneous kernel heading is accepted. The error will probably lead to other kind of error reports, typically when verifying the diagram with the Analyzer tool.
The Organizer detects that the name of the diagram no longer matches the name that is expected in the diagram structure, and marks the diagram icon as mismatch. (A warning is also added to the Organizer Log window.)

4. To correct the mismatch, you have to update the name of the reference symbol accordingly. Use the command Edit Reference Page to bring the page with the reference symbol into view. Locate the reference symbol and rename it accordingly.

For renaming diagrams in a top-down fashion., see Renaming a Diagram Reference Symbol.

Changing the Type of a Diagram

It is possible to re-type a diagram, provided the old and the new types are "compatible" from the SDL Editor's point of view. The basic compatibility criteria is that the old and new type of diagram must both be interaction diagrams or both be flow diagrams. Also checks are made on the pages that are contained in a diagram (some diagram types are allowed to have different types of pages in the same diagram, see Relationship between Diagrams and Pages. The table below summarizes the type changes that are allowed.

case	A diagram of type...	...can be changed to any of:
	SYSTEM	SYSTEM TYPE BLOCK SUBSTRUCTURE BLOCK TYPE PACKAGE
	BLOCK	BLOCK TYPE SYSTEM SUBSTRUCTURE SYSTEM TYPE PACKAGE
	PROCESS	PROCESS TYPE SERVICE PROCEDURE SERVICE TYPE MACRODEFINITION OPERATOR
	SERVICE	SERVICE TYPE PROCESS PROCEDURE PROCESS TYPE MACRODEFINITION OPERATOR
	PROCEDURE	PROCESS SERVICE PROCESS TYPE SERVICE TYPE MACRODEFINITION OPERATOR
	SUBSTRUCTURE	SYSTEM BLOCK SYSTEM TYPE BLOCK TYPE PACKAGE
	MACRODEFINITION	PROCESS SERVICE PROCEDURE PROCESS TYPE SERVICE TYPE OPERATOR
	SYSTEM TYPE	SYSTEM BLOCK SUBSTRUCTURE BLOCK TYPE PACKAGE
	BLOCK TYPE	SYSTEM BLOCK SUBSTRUCTURE SYSTEM TYPE PACKAGE
	PROCESS TYPE	PROCESS SERVICE PROCEDURE SERVICE TYPE MACRODEFINITION OPERATOR
	SERVICE TYPE	SERVICE PROCESS PROCEDURE SERVICE TYPE MACRODEFINITION
	OPERATOR	PROCESS SERVICE PROCEDURE PROCESS TYPE SERVICE TYPE MACRODEFINITION
	PACKAGE	SYSTEM BLOCK SUBSTRUCTURE SYSTEM TYPE BLOCK TYPE

To change the type of a diagram:

1. Select the kernel heading.
2. In the text window, edit the kernel heading text to apply a new type. See the table above for allowed transformations.
3. Deselect the kernel heading. The SDL Editor checks that the type is still valid according to the table above. Any violation of these rules will cause a dialog with the following alternatives to be issued:
• Clicking OK, you are returned to the text window where you should correct the error.
• Clicking Revert, the kernel heading is reverted to its original contents.
• Clicking Ignore, the erroneous kernel heading is accepted. The error will probably lead to other kind of error reports, typically when verifying the diagram with the SDT Analyzer.

Changing the Qualifier of a Diagram

By changing the qualifier that appears in the kernel heading, you can change the context of the diagram.

SDT accepts the two Z.100 notations for a qualifier, namely with and without the surrounding "<< >>".

PROCESS TYPE <<SYSTEM MYSYS/BLOCK MYBLOCK>> Myproc

Alternatively:

PROCESS TYPE SYSTEM MYSYS/BLOCK MYBLOCK Myproc

To change the qualifier:

1. Select the kernel heading.
2. In the text window, edit the kernel heading text to apply the new qualifier.
3. Deselect the kernel heading. The SDL Editor checks that the new qualifier is syntactically correct. Any syntax error will cause a dialog with the following alternatives to be issued.
• Clicking OK, you are returned to the text window where you should correct the error.
• Clicking Revert, the kernel heading is reverted to its original contents.
• Clicking Ignore, the erroneous kernel heading is accepted. The error will probably lead to other kind of error reports, typically when verifying the diagram with the SDT Analyzer.

Renaming a Diagram Reference Symbol

When you change the name of a diagram reference symbol, the SDL Editor checks that the new name is not in conflict with existing symbols. If the reference symbol passes this check, the Organizer structure is updated accordingly.

When renaming diagrams in a top-down fashion, you start by changing the name of a reference symbol. After the reference symbol is renamed, you should also update the referenced diagram's kernel heading accordingly to maintain consistency in the diagram structure.

To rename a diagram reference symbol and the referred diagrams:

1. Select the symbol to be renamed.
2. Change the name of the reference symbol.
3. Deselect the symbol. The SDL Editor checks that the name and type are still unique within the diagram.

If the new name of the reference symbol is accepted, the SDT diagram structure is updated to reflect the nature of the change.

4. To ensure that the change also applies to the referred diagram, you should use the Organizer command Update Headings (see Update Headings). This command verifies and possibly changes the name in the diagram kernel heading against the expected name (which is the one that now is shown in the reference symbol). The mismatch between the name of the diagram is reported in a dialog:

Figure 374 : The mismatch in headings is reported

• Correct the mismatch by clicking Update.
Note that if you select not to update the kernel heading, you simply postpone the problem.

For renaming in a bottom-up way, see Changing the Name of a Diagram.

Removing Symbols

When you remove a diagram reference symbol, the underlying structure is also removed from the Organizer structure. However, the hierarchy will be restored if the remove operation is restored by doing Undo.

1. Select the symbol(s) to be removed.
2. Select Clear from the Edit menu. The symbol(s) are removed, as well as the lines that were connected to these symbols.

Printing Symbols

A selection of symbols can be printed. This allows for instance to print only the portion of a diagram which is of interest.

1. Select the symbols to be printed.
2. Select Print from the File menu.
3. In the Print Dialog, click the Setup button. The Print Setup dialog will be issued. In the dialog, select the Print only selected symbols option.
4. Adjust, if necessary, other Print options and click the OK and Print buttons. See Printing a Diagram for more information.

Working with Lines

The main operations provided by the SDL Editor on lines, and their associated text attributes are:

• Selecting Lines
• Drawing Lines
• Re-Routing and Reshaping Lines
• Redirecting and Bidirecting Lines
• Adjusting Lines to the Grid

In addition, text editing functions are provided for the text associated with the lines.

Operations on lines are performed slightly different depending if you are editing

• flow pages
• interaction pages

The main difference between the two is that flow pages may only allow vertical and horizontal lines.

Some restrictions also apply when connecting symbols in flow pages, depending upon whether or not the syntax checking is enabled

Selecting Lines

You select lines and extend and reduce selections of lines with standardized selection commands.

Selecting a Line That Has Associated Objects

Consider the following when selecting a line which has text associated with it:

• When you select a line, you implicitly select the associated attributes as well. A text cursor is inserted directly in the text associated with a line, and the text window will be updated to contain the text.
• If you point to a line associated with a symbol, you will select the line, not the symbol. The process of selecting symbols is described in Selecting Symbols.
• If you point to the text associated with a line, you will select the text object, not the line.

Displaying Selected Line Attributes

Selected line attributes are displayed as follows:

• Each text attribute is displayed inside a text selection rectangle.
• The following attributes are displayed with a filled selection square:
• Each arrow (on interaction pages only)
• Each line breakpoint (on interaction pages only)
• The middle of each line segment (on interaction pages only a tiny selection square marks the handle to create a new breakpoint)
• The middle of each line segment (on flow pages only)

Selecting Overlapping Objects

On a page, objects may overlap each other. A layer order is defined so that it is possible to determine how overlapping objects are stacked.

Drawing Lines

This section describes how to interconnect symbols with lines. Two modes are supported in the SDL Editor.

Drawing a Line with Syntax Checking Enabled

The way that you draw a line differs somewhat depending upon whether you are working on an interaction page or a flow page. The differences will be pointed out later in this section.

When syntax checking is enabled, you are only allowed to draw lines that are correct according to the SDL rules. When syntax checking is disabled, the rules are less strict.

Designating the Start Point

1. Select the symbol from which the line will originate.
2. Point to the handle and drag it to begin forming the line. The line that is formed ends where the mouse pointer is located. Note that the mouse button can be released as soon as you have moved the mouse pointer.

Designating the End Point

1. Designate the start point. See previous section.
2. You can route the line and specify where it will end either automatically or manually.

• To route the line automatically:
• Click any valid target symbol to specify where the line should end.

A symbol is valid if the syntax rules enforced by the SDL Editor at edit-time allows the drawing of a line from the first symbol to the second symbol.

• To route the line manually, indicating where line breakpoints are to be inserted, follow the steps below.
1. To enter manual mode, click any location in the drawing area other than a valid destination symbol.
2. Click each location where you want to insert a line breakpoint.
3. Click on a valid destination symbol.

As long as you do not point to a valid destination symbol, the line will be routed from the selected symbol to the current mouse position. The automatic line drawing facility will determine the layout of the line until you have inserted the first breakpoint.

Figure 375 : Drawing a line in manual mode

Drawing Multiple Lines

When you draw lines between symbols and keep the <Control> key pressed, the start point for the next line to draw is automatically transferred to the target symbol.

This feature provides the easiest way to draw multiple lines in rapid succession.

Differences between Flow and Interaction in Line Drawing

The way that you draw a line differs somewhat depending upon whether you are working on an interaction page or a flow page:

• On an interaction page, you can draw lines in all possible directions.
• On a flow page, you can only draw lines horizontally or vertically. The last line breakpoint, even if determined manually, will be adjusted so that the destination symbol is connected correctly, normally in the middle of the upper edge of the symbol. Exceptions are made for comment and text extension symbols, which are connected to the center of the right or left edge of the symbol.

Cancelling the Line Drawing Operation

You can cancel a line drawing operation in either of the following ways:

• Press <ESC>.
• Double-click any part of the drawing area that is not a valid destination symbol.

Drawing a Line with Syntax Checking Disabled

The process of drawing a line is the same regardless of whether or not syntax checking is enabled. To enable and disable syntax checking, see Turning Syntax Checking On and Off.

When drawing lines with syntax checking disabled, you may interconnect symbols in any way you want.

Re-Routing and Reshaping Lines

Reshaping a line refers to changing the path that the line follows. This operation does not affect the endpoints of the line. The flow lines only move in either a horizontal or vertical way.

Re-routing a line denotes changing the ending point of the line from one symbol to another symbol.

Reshaping a Flow Line

1. Point to one of the segments of the line.
2. Press the mouse and, holding down the mouse button, drag the segment to the required position.
3. Release the mouse button.

Re-Routing a Flow Line

You can move the ending point of a flow line, and reconnect it to any valid destination symbol. You can redraw the line either manually or automatically.

To move a line's ending point:

1. Point at the ending point that you want to reconnect.
2. Press the mouse. Start dragging the ending point. As soon as you move the mouse, the line's last segment follows the mouse motion and you can release the mouse button.
3. You can click additional line breakpoints where you like.
4. Click the destination symbol to complete the operation. If it is a valid symbol, the line will be re-routed automatically.

Re-Routing an Interaction Line

You can move any starting or endpoint to and from a symbol and the environment.

1. Point to the starting or ending point of the line.
2. Press the mouse and, holding the mouse down, drag it to the desired symbol.
3. If required, click to add line breakpoints at desired positions.
4. Terminate by clicking on the new symbol. The line is redrawn accordingly.

Moving an Interaction Line Breakpoint

To move a line breakpoint in an interaction page:

1. Point to the breakpoint that you want to move.
2. Press the mouse and drag the breakpoint to the desired location.
3. Release the mouse button to redraw the line.

Figure 376 : Moving an interaction line breakpoint

Inserting Breakpoints in an Interaction Line

1. Point at the middle of a line segment. When the line is selected a tiny selection square will be displayed at this point.
2. Press the mouse and drag it to shape the breakpoint.

An alternative way to insert breakpoints on an interaction line:

1. Press <Ctrl>
2. Point in a line segment where you want to insert a new breakpoint.
3. Press the mouse and drag it to shape the breakpoint.
4. Release the <Ctrl> key.

Moving an Interaction Line Segment

You can move a line segment in an interaction page as long as it is not a starting segment or ending segment.

1. Point to the line segment to be moved.
2. Press the mouse and drag the line segment to the desired location.
3. Release the mouse button. The line segment and the adjacent line segments are redrawn accordingly.

Moving Arrows

Arrows on channels, gates and signal routes denote the orientation of flow on that line. They are assigned default locations when creating the line.

You can manually move arrows on channels along the line.

1. Point to the arrow.
2. Press the mouse. Still holding the mouse down, drag it until the arrow reaches the new place.
3. Release the mouse. The arrow and the signal list are redrawn accordingly.

To create a non-delay channel you simply drag the arrow to the starting or ending breakpoint.

Moving a Line and Its Connection Point

A channel or a signal route may be connected to a connection point (usually located close to the line, immediately outside the frame).

Figure 377 : A signal route connected to a connection point.

Moving the line's ending point with the connection point unselected will move the line only and create a new connection point. The old connection point is removed.

To move the line and the connection point:

1. Click on the ending point of the line. Make sure the connection point is selected (i.e. the selection rectangle appears).
2. Drag the line's ending point to the new location. The connection point follows the mouse motion as well.
• If the line's new ending point coincides with a gate symbol and the connection point has a name, a dialog is issued. The meaning of this message is described in Connecting a Gate Symbol with a Channel or Signal Route.

Moving a Line Text Attribute

A line text attribute is a textual element that is related to a line. The following lines have associated text attributes:

• Gates
• Channels
• Signal routes
• Flow lines after decision, transition option and macro call symbols.

When drawing a line, the SDL Editor positions the text attribute close to the source symbol and originating line, so that it is easy to identify what line the text attribute is related to. You are however free to move the text attribute to any location in the drawing area within the frame.

To move a line text attribute:

1. Point to the text attribute.
2. Press the mouse, and, still holding the mouse down, drag the text attribute to its new location.
3. Release the mouse button.

Redirecting and Bidirecting Lines

When you add a channel or signal route to an interaction diagram, the line is initially drawn in a uni-directional manner, originating from the source symbol and pointing to the target symbol.

The only way to draw a line from the environment to a symbol is to first draw it from the symbol and then redirect it.

Redirecting a Line

1. Select the line
2. Choose Redirect from the Edit menu. The line is redirected.

Figure 378  : Redirecting a line

Bidirecting a Line

1. Select the line.
2. Choose Bidirect from the Edit menu. The line is bidirected.
3. Fill in the second signal list.

Figure 379  : Bidirecting a line

Uni-Directing a Bidirected Line

1. Select the arrow denoting the signal list you want to remove (the corresponding signal list is displayed with a selection box).
2. Select Clear from the Edit menu.

Adjusting Lines to the Grid

When you move or reshape interaction lines, the line breakpoints are adjusted to the line grid, which cannot be disabled and has a fixed resolution of 2.5 mm.

Flow line segments and line text attributes are always placed so that they match the resolution of the line grid.