Mermaid CLI - how do you escape characters? - diagramming

Question

I'm using the Mermaid CLI to generate a flowchart (http://knsv.github.io/mermaid/flowchart.html). It works great, but I can't figure out how to get special characters (percent signs, parenthesis, etc) working as text within a node.
For illustration purposes here is a sample flowchart definition for Mermaid (filename is example.mermaid):
graph TD
question1{Gas tank less than 1/8?}
action1[Fill tank to 100%]
question1-- Yes -->action1
When I run mermaid on that file, I get this error (it blows up on the percent sign):
My-MacBook-Pro:mermaid mark$ mermaid example.mermaid
Error: Parse error on line 3:
...on1[Fill tank to 100%]question1-- Yes -
-----------------------^
Expecting 'QUOTE', 'TAG_END', 'TAG_START', 'MULT', 'EQUALS', 'PLUS', 'DOT', 'BRKT', 'COLON', 'ALPHA', 'COMMA', 'NUM', 'CLICK', 'CLASS', 'CLASSDEF', 'LINKSTYLE', 'STYLE', 'PIPE', 'THICK_ARROW_OPEN', 'THICK_ARROW_CROSS', 'THICK_ARROW_CIRCLE', 'THICK_ARROW_POINT', 'DOTTED_ARROW_OPEN', 'DOTTED_ARROW_CROSS', 'DOTTED_ARROW_CIRCLE', 'DOTTED_ARROW_POINT', 'ARROW_OPEN', 'ARROW_CROSS', 'ARROW_CIRCLE', 'ARROW_POINT', '==', '-.', '--', 'MINUS', 'DIAMOND_STOP', 'DIAMOND_START', 'PE', 'PS', 'SQE', 'SQS', 'end', 'subgraph', 'NEWLINE', 'TAGSTART', 'TAGEND', 'DIR', 'SPACE', 'GRAPH', 'EOF', 'SEMI', got 'PCT'
../dist/mermaid.full.js:14712 in parseError
../dist/mermaid.full.js:14782 in parse
../dist/mermaid.full.js:13260
../dist/mermaid.full.js:16846
../dist/mermaid.full.js:16889
phantomjs://webpage.evaluate():23 in executeInPage
phantomjs://webpage.evaluate():29
phantomjs://webpage.evaluate():29
PHANTOM ERROR: TypeError: 'null' is not an object (evaluating 'element.setAttribute')
TRACE:
-> /usr/local/lib/node_modules/mermaid/lib/phantomscript.js: 149 (in function resolveSVGElement)
-> /usr/local/lib/node_modules/mermaid/lib/phantomscript.js: 69
I tried escaping the percent sign, like this:
action1[Fill tank to 100&]
But then I get the same error on the semicolon. Any thoughts on how I can escape those characters to make it work? Thanks!

Answer 1

Use quotation marks "" to enclose your text and escape special characters, e.g. in your example:
graph TD
question1{"Gas tank less than 1/8?"}
action1["Fill tank to 100%"]
question1-- Yes -->action1
will produce this diagram:
This is now documented in the official documentation.

Answer 2

Here are more examples of escaping / quoting special characters. The code
flowchart LR
A["For most symbols double quotes are enough: ```~`!##$%^*()[]{}|\/:;'?<>,.+=-_"]
B["["&quot;&lt;<br>&gt;&amp;&frac12;#35;189;"]"]
B --> C[""<<br>>&½#189;"]
produces
Using this method most unicode characters (including non-ASCII) can be included using either unicode entity or markdown #code; syntax (both ways are illustrated using the character ½ in the diagram above). See also the official documentation.
Disclaimer: I didn't test it in Mermaid CLI. Tested in markdown-viewer and Mermaid live editor.

Answer 3

That was an issue with early mermaid versions. I tried your example code with mermaid 0.4.0 where it renders fine. I would recommend upgrading.