The goal in this lab is to get a grammar working for a simple programming language.
Create a grammar file called S.g4
Make a rule called stat that matches return statements of the form return expr ; and assignment statements of the form ID = expr ; Use the following expression rule:
expr: expr '*' expr
| expr '+' expr
| INT
| ID
;
Define lexical rules INT and ID according to what you see in the ANTLR 4 reference book. Create a whitespace lexical rule to skip whitespace characters such as space and newline.
Finally, make a rule called code that matches one or more stats.
Test your grammar using code as the start symbol on input sentences like:
x = 3;
return x*10;
The parse tree should look like:
