[TxMt] Unit Testing Grammars: GrammarTestMate

Allan Odgaard mailinglist at textmate.org
Sat May 8 18:36:59 UTC 2010

The topic of unit testing grammars has often been brought up and I  
finally did a CLI tool for running a file through the TM parser.

The tool is here: http://updates.textmate.org/gtm.bz2

It reads the text to be parsed from stdin and takes as argument paths  
to tmGrammar files which should be loaded. If the -g/--grammar option  
is not given, the first grammar specified will be used to parse the  

Output is the parsed document in the pseudo-XML format that TextMate  
commands can receive as input.

Presently the -t and -d options are not implemented.


     gtm < test.c C.tmbundle/Syntaxes/C.plist
     gtm < test.cc -g source.c++ C.tmbundle/Syntaxes/{C,C++}.plist

I plan to also make this a profiling tool so that it can list how much  
time is spent in each rule, but this is secondary to the current  
agenda of providing the basis for grammar unit tests.

I am announcing this to get some input on how we can build a good unit  
testing system. My concern is that we’ll either make really simple  
tests that never break (it’s generally complex interplays of rules  
that cause problems), or we’ll have fully parsed complex documents as  
the “expected output” and can’t make changes to the grammars w/o  
pretty much rewriting all the tests.

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