[RACC] Multiple entry points?

[Carlos]

Hi,

imagine I have a parser like this:

program: PROGRAM name '{' statements '}' { ... }
;

statements: statement { ... }
| statements statement { ... }
;

statement: ...

and I want to parse a single statement. How I can tell the parser to
start at 'statement' and return?

Thanks.

 

[Charles Comstock]

Hi,

imagine I have a parser like this:

program: PROGRAM name '{' statements '}' { ... }
;

statements: statement { ... }
| statements statement { ... }
;

statement: ...

and I want to parse a single statement. How I can tell the parser to
start at 'statement' and return?

Thanks.

I think,

start statement

will do that, though if statement includes a reference to statements
obviously it will recurs.

Charlie

 

[Minero Aoki]

Hi,

In mail "[RACC] Multiple entry points?"

imagine I have a parser like this:

program: PROGRAM name '{' statements '}' { ... }
;

statements: statement { ... }
| statements statement { ... }
;

statement: ...

and I want to parse a single statement. How I can tell the parser to
start at 'statement' and return?

Use dummy token.

targets: PARSE_PROGRAM program /* PARSE_PROGRAM is a dummy token */
| PARSE_STATEMENT statement /* PARSE_STATEMENT is a dummy token */
;

program: ....

statement: ....

When you want to parse "program", a lexer returns PARSE_PROGRAM at first.
When you want to parse "statement", a lexer returns PARSE_STATEMENT at first.


Regards,
Minero Aoki

 

[Carlos]

program: PROGRAM name '{' statements '}' { ... }

Use dummy token.

targets: PARSE_PROGRAM program /* PARSE_PROGRAM is a dummy token */
| PARSE_STATEMENT statement /* PARSE_STATEMENT is a dummy token */
;

program: ....

statement: ....

When you want to parse "program", a lexer returns PARSE_PROGRAM at first.
When you want to parse "statement", a lexer returns PARSE_STATEMENT at first.

A simple and clever solution! Thank you very much!