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|
header {
#include "MyAST.h"
}
options {
language="Cpp";
}
{
#include <iostream>
}
class LangParser extends Parser;
options {
codeGenMakeSwitchThreshold = 3;
codeGenBitsetTestThreshold = 4;
ASTLabelType = "RefMyAST";
buildAST = true;
}
block
: LCURLY^ ( statement )* RCURLY!
;
statement
: expr SEMI!
| "if"^ LPAREN! expr RPAREN! statement
( "else"! statement )?
| "while"^ LPAREN! expr RPAREN! statement
|! b:block { #statement = b_AST; }
// do some manual tree returning
;
expr: assignExpr
;
assignExpr
: aexpr (ASSIGN^ assignExpr)?
;
aexpr
: mexpr (PLUS^ mexpr)*
;
mexpr
: atom (STAR^ atom)*
;
atom: ID
| INT
;
{
#include <iostream>
void LangWalker::printAST( RefMyAST ast )
{
ANTLR_USE_NAMESPACE(std)cout << "Found " << getTokenName(ast->getType())
<< " '" << ast->getText()
<< "' at line " << ast->getLine()
<< ANTLR_USE_NAMESPACE(std)endl;
}
}
class LangWalker extends TreeParser;
options {
ASTLabelType = "RefMyAST";
}
{
void printAST( RefMyAST ast );
}
block
: #( LCURLY ( stat )+ )
;
stat: #("if" expr stat (stat)?)
| #("while" expr stat)
| expr
| block
;
expr: #(asgn:ASSIGN expr expr) { printAST(asgn); }
| #(plus:PLUS expr expr) { printAST(plus); }
| #(star:STAR expr expr) { printAST(star); }
| a:ID { printAST(a); }
| b:INT { printAST(b); }
;
class LangLexer extends Lexer;
WS_ : (' '
| '\t' { tab(); }
| '\n' { newline(); }
| '\r')
{ $setType(ANTLR_USE_NAMESPACE(antlr)Token::SKIP); }
;
LPAREN: '('
;
RPAREN: ')'
;
LCURLY: '{'
;
RCURLY: '}'
;
STAR: '*'
;
PLUS: '+'
;
ASSIGN
: '='
;
SEMI: ';'
;
COMMA
: ','
;
protected
ESC : '\\'
( 'n'
| 'r'
| 't'
| 'b'
| 'f'
| '"'
| '\''
| '\\'
| ('0'..'3') ( DIGIT (DIGIT)? )?
| ('4'..'7') (DIGIT)?
)
;
protected
DIGIT
: '0'..'9'
;
INT : (DIGIT)+
;
ID
options {
testLiterals = true;
}
: ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*
;
|
