如何编写规则以在 ANTLR 中定义方法

Question

I am creating a DSL with ANTLR and I want to define the following syntax

// study without parameters
study()
// study  with a single parameter
study(x = 1)
// study with several parameters
study(x = 1, x = 2)

here my grammer ,it allows the following input : study(x=1x=2)

study: 'study' '(' ( assign* | ( assign (',' assign)*) ) ')' NEWLINE;
assign: ID '=' (INT  | DATA );
INT :   [0-9]+ ;
DATA    : '"' ID '"' | '"' INT '"';
ID  :   [a-zA-Z]+ ;

Answer 1

Your grammar allows study(x=1x=2) because assign* matches x=1x=2 . If you don't want to allow input like that, you should remove the assign* alternative. To allow empty parameter lists, you can just make everything between the parentheses optional:

study: 'study' '(' (assign (',' assign)*)? ')' NEWLINE;