No grammar? No problem (2013)
As long as you’re willing to roll up your sleeves and take a look at the source code of the compiler in question, you can frequently resolve your question for less effort than it would have taken to look up the syntax in the manual (and it’s guaranteed to be up-to-date too!) When the code in question has very distinctive keywords (as this one does), a grep will often do the trick:
File extensions can also be dead giveaways; GHC uses a parser generator named Happy, and the file extension of Happy files is :
From there, we can search the file for keywords or symbols (check for the string token name if a lexer is used; also, make sure to quote alphanumeric literals). Alternately, you might hope there is a useful comment in the source file which explains what is up:
The second example is for STG, which you can ask GHC to print out using .