ANTLR语法后缀
|
遇到问题时，我正在为一种小语言编写简单的语法。当我尝试解释时，它会抛出一个“ 0”。哦，这是ANTLRWorks 3。
另外-我指定该语言应为Python，但仍然可以使用Java :(为什么？
这是输入：
program Test1 =
const t1 : int := 1;
const t2 : int := 2;
var x, y, z : int;
begin
x := 41;
y := 10;
z := 2 4 *;
end Test1.
grammar lang;
options {
language=Python;
output=AST;
ASTLabelType=CommonTree;
}
tokens {DECL;} // an imaginary node
start : decl ;
decl : type ID \';\' -> ^(DECL type ID)
;
type : INTTYPE // automatic tree construction builds a node for this rule
| FLOATTYPE
;
program
: \'program\' ID \'=\'
(const | variable)*
\'begin\'
statement*
\'end\' ID \'.\'
;
const
: \'const\' ID \':\' type \':=\' expr \';\'
;
variable
: \'var\' ID (\',\' ID)* \':\' type \';\'
;
statement
: assignment
;
assignment
: ID \':=\' expr \';\'
;
// expressions....fun!
term
: ID
| expr
| INTTYPE
;
negation
: \'not\'* term
;
unary
: (\'+\' | \'-\')* negation
;
mult
: unary (unary (\'*\' | \'/\' | \'mod\'))*
;
add
: mult (mult (\'+\' | \'-\'))*
;
relation
: add (add (\'==\' | \'!=\' | \'<\' | \'<=\' | \'>=\' | \'>\'))*
;
expr
: relation (relation (\'and\' | \'or\'))*
;
INTTYPE : \'int\' ;
FLOATTYPE : \'float\' ;
ID : (\'a\'..\'z\' | \'A\'..\'Z\') (\'a\'..\'z\' | \'A\'..\'Z\' | \'0\'..\'9\')* ;
INT : \'0\'..\'9\'+ ;
WS : (\' \'|\'\\n\' | \'\\t\') {$channel=HIDDEN;} ;
没有找到相关结果
已邀请:
1 个回复
倾坞髓
grammar lang; options { language=Python; output=AST; } tokens { PROGRAM; STATS; DECL; ASSIGN; EXPR; } program : \'program\' id=ID \'=\' decl* \'begin\' statement* \'end\' ID \'.\' -> ^(PROGRAM $id ^(DECL decl*) ^(STATS statement*)) ; decl : const | variable ; type : INTTYPE | FLOATTYPE ; const : \'const\' ID \':\' type \':=\' expr \';\' -> ^(\'const\' type ID expr) ; variable : \'var\' ID (\',\' ID)* \':\' type \';\' -> ^(\'var\' type ID+) ; statement : assignment ; assignment : ID \':=\' expr \';\' -> ^(ASSIGN ID expr) ; expr : exprAtom+ -> ^(EXPR exprAtom+) ; exprAtom : operand | operator ; operand : INT | ID ; operator : \'and\' | \'or\' | \'==\' | \'!=\' | \'<\' | \'<=\' | \'>=\' | \'>\' | \'+\' | \'-\' | \'*\' | \'/\' | \'mod\' | \'not\' ; INTTYPE : \'int\' ; FLOATTYPE : \'float\' ; ID : (\'a\'..\'z\' | \'A\'..\'Z\') (\'a\'..\'z\' | \'A\'..\'Z\' | \'0\'..\'9\')* ; INT : \'0\'..\'9\'+ ; WS : (\' \'|\'\\n\' | \'\\t\') {$channel=HIDDEN;} ;#!/usr/bin/env python import antlr3 from antlr3 import * from antlr3.tree import * from langLexer import * from langParser import * def print_level_order(tree, indent): print \'{0}{1}\'.format(\' \'*indent, tree.text) for child in tree.getChildren(): print_level_order(child, indent+1) input = \"\"\" program Test1 = const t1 : int := 1; const t2 : int := 2; var x, y, z : int; begin x := 41; y := 10; z := 2 4 *; end Test1. \"\"\" char_stream = antlr3.ANTLRStringStream(input) lexer = langLexer(char_stream) tokens = antlr3.CommonTokenStream(lexer) parser = langParser(tokens) tree = parser.program().tree print_level_order(tree, 0)PROGRAM Test1 DECL const int t1 EXPR 1 const int t2 EXPR 2 var int x y z STATS ASSIGN x EXPR 41 ASSIGN y EXPR 10 ASSIGN z EXPR 2 4 *