コンパイラ理論クラスの最後の割り当てでは、Javaの小さなサブセット（MiniJavaではない）用のコンパイラを作成します。私たちの教授は私たちが望むどんなツールでも使うオプションを私たちに与えてくれました、そしてたくさんのことを調べた後、私はANTLRに落ち着きました。スキャナーとパーサーを稼働させ、パーサーがASTを出力することに成功しました。ツリー文法ファイルをコンパイルしようとして立ち往生しています。基本的な考え方は、パーサーから文法規則をコピーし、ほとんどのコードを削除して、書き換え規則をそのままにしておくことだと理解していますが、コンパイルしたくないようです（offendingTokenエラー）。私は正しい方向に進んでいますか？些細なことを見逃していますか？
ツリー文法：
tree grammar J0_SemanticAnalysis;
options {
language = Java;
tokenVocab = J0_Parser;
ASTLabelType = CommonTree;
}
@header
{
package ritterre.a4;
import java.util.Map;
import java.util.HashMap;
}
@members
{
}
walk
: compilationunit
;
compilationunit
: ^(UNIT importdeclaration* classdeclaration*)
;
importdeclaration
: ^(IMP_DEC IDENTIFIER+)
;
classdeclaration
: ^(CLASS IDENTIFIER ^(EXTENDS IDENTIFIER)? fielddeclaration* methoddeclaration*)
;
fielddeclaration
: ^(FIELD_DEC IDENTIFIER type visibility? STATIC?)
;
methoddeclaration
: ^(METHOD_DEC IDENTIFIER type visibility? STATIC? ^(PARAMS parameter+)? body)
;
visibility
: PRIVATE
| PUBLIC
;
parameter
: ^(PARAM IDENTIFIER type)
;
body
: ^(BODY ^(DECLARATIONS localdeclaration*) ^(STATEMENTS statement*))
;
localdeclaration
: ^(DECLARATION type IDENTIFIER)
;
statement
: assignment
| ifstatement
| whilestatement
| returnstatement
| callstatement
| printstatement
| block
;
assignment
: ^(ASSIGN IDENTIFIER+ expression? expression)
;
ifstatement
: ^(IF relation statement ^(ELSE statement)?)
;
whilestatement
: ^(WHILE relation statement)
;
returnstatement
: ^(RETURN expression?)
;
callstatement
: ^(CALL IDENTIFIER+ expression+)
;
printstatement
: ^(PRINT expression)
;
block
: ^(STATEMENTS statement*)
;
relation
// : expression (LTHAN | GTHAN | EQEQ | NEQ)^ expression
: ^(LTHAN expression expression)
| ^(GTHAN expression expression)
| ^(EQEQ expression expression)
| ^(NEQ expression expression)
;
expression
// : (PLUS | MINUS)? term ((PLUS | MINUS)^ term)*
: ^(PLUS term term)
| ^(MINUS term term)
;
term
// : factor ((MULT | DIV)^ factor)*
: ^(MULT factor factor)
| ^(DIV factor factor)
;
factor
: NUMBER
| IDENTIFIER (DOT IDENTIFIER | LBRAC expression RBRAC)?
| NULL
| NEW IDENTIFIER LPAREN RPAREN
| NEW (INT | IDENTIFIER) (LBRAC RBRAC)?
;
type
: (INT | IDENTIFIER) (LBRAC RBRAC)?
| VOID
;
パーサー文法：
parser grammar J0_Parser;
options
{
output = AST; // Output an AST
tokenVocab = J0_Scanner; // Pull Tokens from Scanner
//greedy = true; // forcing this throughout?! success!!
//cannot force greedy true throughout. bad things happen and the parser doesnt build
}
tokens
{
UNIT;
IMP_DEC;
FIELD_DEC;
METHOD_DEC;
PARAMS;
PARAM;
BODY;
DECLARATIONS;
STATEMENTS;
DECLARATION;
ASSIGN;
CALL;
}
@header { package ritterre.a4; }
// J0 - Extended Specification - EBNF
parse
: compilationunit EOF -> compilationunit
;
compilationunit
: importdeclaration* classdeclaration*
-> ^(UNIT importdeclaration* classdeclaration*)
;
importdeclaration
: IMPORT IDENTIFIER (DOT IDENTIFIER)* SCOLON
-> ^(IMP_DEC IDENTIFIER+)
;
classdeclaration
: (PUBLIC)? CLASS n=IDENTIFIER (EXTENDS e=IDENTIFIER)? LBRAK (fielddeclaration|methoddeclaration)* RBRAK
-> ^(CLASS $n ^(EXTENDS $e)? fielddeclaration* methoddeclaration*)
;
fielddeclaration
: visibility? STATIC? type IDENTIFIER SCOLON
-> ^(FIELD_DEC IDENTIFIER type visibility? STATIC?)
;
methoddeclaration
: visibility? STATIC? type IDENTIFIER LPAREN (parameter (COMMA parameter)*)? RPAREN body
-> ^(METHOD_DEC IDENTIFIER type visibility? STATIC? ^(PARAMS parameter+)? body)
;
visibility
: PRIVATE
| PUBLIC
;
parameter
: type IDENTIFIER
-> ^(PARAM IDENTIFIER type)
;
body
: LBRAK localdeclaration* statement* RBRAK
-> ^(BODY ^(DECLARATIONS localdeclaration*) ^(STATEMENTS statement*))
;
localdeclaration
: type IDENTIFIER SCOLON
-> ^(DECLARATION type IDENTIFIER)
;
statement
: assignment
| ifstatement
| whilestatement
| returnstatement
| callstatement
| printstatement
| block
;
assignment
: IDENTIFIER (DOT IDENTIFIER | LBRAC a=expression RBRAC)? EQ b=expression SCOLON
-> ^(ASSIGN IDENTIFIER+ $a? $b)
;
ifstatement
: IF LPAREN relation RPAREN statement (options {greedy=true;} : ELSE statement)?
-> ^(IF relation statement ^(ELSE statement)?)
;
whilestatement
: WHILE LPAREN relation RPAREN statement
-> ^(WHILE relation statement)
;
returnstatement
: RETURN expression? SCOLON
-> ^(RETURN expression?)
;
callstatement
: IDENTIFIER (DOT IDENTIFIER)? LPAREN (expression (COMMA expression)*)? RPAREN SCOLON
-> ^(CALL IDENTIFIER+ expression+)
;
printstatement
: PRINT LPAREN expression RPAREN SCOLON
-> ^(PRINT expression)
;
block
: LBRAK statement* RBRAK
-> ^(STATEMENTS statement*)
;
relation
: expression (LTHAN | GTHAN | EQEQ | NEQ)^ expression
;
expression
: (PLUS | MINUS)? term ((PLUS | MINUS)^ term)*
;
term
: factor ((MULT | DIV)^ factor)*
;
factor
: NUMBER
| IDENTIFIER (DOT IDENTIFIER | LBRAC expression RBRAC)?
| NULL
| NEW IDENTIFIER LPAREN RPAREN
| NEW (INT | IDENTIFIER) (LBRAC RBRAC)?
;
type
: (INT | IDENTIFIER) (LBRAC RBRAC)?
| VOID
;