Deactivating participants starting with "x" causes syntax error in sequence diagram

[antonhattendorf]

Describe the bug In sequence diagrams: When deactivating participants starting with "x" using the shortcut version with a message a syntax error is caused.

To Reproduce In live editor

sequenceDiagram
	xAlice->>+John: John, can you hear me?
	John-->>-xAlice: Hi Alice, I can hear you!

creates a "Syntax Error".

The following workaround (without the shortcut) is possible:

sequenceDiagram
	xAlice->>+John: John, can you hear me?
	John-->>xAlice: Hi Alice, I can hear you!
	deactivate John

Also letting "xAlice" not start with "x" works or adding a space before the "x".

Expected behavior graph is drawn

Desktop (please complete the following information):

• OS: Debian stretch
• Browser Firefox
• Version 73.0.1

Additional context I assume the parser mixes this with the "-x" symbol.

[vassudanagunta]

I'm not sure if this is a workaround or the solution: simply use spaces to disambiguate. The following renders fine:

sequenceDiagram
xAlice ->>+ John: John, can you hear me?
John -->>- xAlice: Hi Alice, I can hear you!

[jgreywolf]

@antonhattendorf Can you try @vassudanagunta suggestion and see if that works for you? If so, I am thinking that we would close this as Wont Fix

[nirname]

I consider this is a parsing error that could be fixed. But probably this is not what we really need

Firstly, you get pretty descriptive parsing error

Expecting '+', '-', 'ACTOR', got 'SOLID_CROSS'

In programming languages variables cannot be named after reserved words or operators. -x as a special operator. Think about actor as about variable.

To avoid this and use keywords inside actors there is a special syntax:

sequenceDiagram

participant Alice as Alice whatever you want including arrows -- >, crosses -x etc
Alice ->>+ John: John, can you hear me?
John -->>- Alice: Hi Alice, I can hear you!

sequenceDiagram

participant Alice as Alice whatever you want including arrows -- >, crosses -x etc
Alice ->>+ John: John, can you hear me?
John -->>- Alice: Hi Alice, I can hear you!