Disambiguating unary and binary minus

[wh5a]

A statement like "cu1(-pi) q[0], q[1];" cannot be parsed correctly, unless we insert a space like so: "cu1(- pi) q[0], q[1];".

The grammar needs to be changed. A quick search found some discussions:
https://stackoverflow.com/questions/32166738/disambiguating-unary-and-binary-minus-in-antlr4-grammar
https://stackoverflow.com/questions/27478834/how-compiler-distinguishes-minus-and-negative-number-during-parser-process