allow arrow omission in $foo[10]->('foo') etc. (but not in

foo()->()); rework grammar to remove conflicts
	Message-ID: <14232.54970.771570.548676@alias-2.pr.mcs.net>
	Subject: [PATCH _57, long] Re: optional arrow asymmetry

p4raw-id: //depot/perl@3767

1 files changed, 63 insertions, 45 deletions

diff --git a/perly.y b/perly.y
index 2594c087f7..9df012c3aa 100644
--- a/perly.y
+++ b/perly.y
@@ -43,7 +43,7 @@
 #endif
 %}
 
-%token <ival> '{' ')'
+%token <ival> '{'
 
 %token <opval> WORD METHOD FUNCMETH THING PMFUNC PRIVATEREF
 %token <opval> FUNC0SUB UNIOPSUB LSTOPSUB
@@ -59,12 +59,15 @@
 %type <ival> prog decl local format startsub startanonsub startformsub
 %type <ival> remember mremember '&'
 %type <opval> block mblock lineseq line loop cond else
-%type <opval> expr term scalar ary hsh arylen star amper sideff
+%type <opval> expr term subscripted scalar ary hsh arylen star amper sideff
 %type <opval> argexpr nexpr texpr iexpr mexpr mnexpr mtexpr miexpr
 %type <opval> listexpr listexprcom indirob listop method
 %type <opval> formname subname proto subbody cont my_scalar
 %type <pval> label
 
+%nonassoc PREC_LOW
+%nonassoc LOOPEX
+
 %left <ival> OROP
 %left ANDOP
 %right NOTOP
@@ -88,7 +91,9 @@
 %right <ival> POWOP
 %nonassoc PREINC PREDEC POSTINC POSTDEC
 %left ARROW
+%nonassoc <ival> ')'
 %left '('
+%left '[' '{'
 
 %% /* RULES */
 
@@ -332,14 +337,14 @@ expr	:	expr ANDOP expr
 			{ $$ = newLOGOP(OP_AND, 0, $1, $3); }
 	|	expr OROP expr
 			{ $$ = newLOGOP($2, 0, $1, $3); }
-	|	argexpr
+	|	argexpr %prec PREC_LOW
 	;
 
 argexpr	:	argexpr ','
 			{ $$ = $1; }
 	|	argexpr ',' term
 			{ $$ = append_elem(OP_LIST, $1, $3); }
-	|	term
+	|	term %prec PREC_LOW
 	;
 
 listop	:	LSTOP indirob argexpr
@@ -383,6 +388,49 @@ method	:	METHOD
 	|	scalar
 	;
 
+subscripted:    star '{' expr ';' '}'
+			{ $$ = newBINOP(OP_GELEM, 0, $1, scalar($3)); }
+	|	scalar '[' expr ']'
+			{ $$ = newBINOP(OP_AELEM, 0, oopsAV($1), scalar($3)); }
+	|	term ARROW '[' expr ']'
+			{ $$ = newBINOP(OP_AELEM, 0,
+					ref(newAVREF($1),OP_RV2AV),
+					scalar($4));}
+	|	subscripted '[' expr ']'
+			{ $$ = newBINOP(OP_AELEM, 0,
+					ref(newAVREF($1),OP_RV2AV),
+					scalar($3));}
+	|	scalar '{' expr ';' '}'
+			{ $$ = newBINOP(OP_HELEM, 0, oopsHV($1), jmaybe($3));
+			    PL_expect = XOPERATOR; }
+	|	term ARROW '{' expr ';' '}'
+			{ $$ = newBINOP(OP_HELEM, 0,
+					ref(newHVREF($1),OP_RV2HV),
+					jmaybe($4));
+			    PL_expect = XOPERATOR; }
+	|	subscripted '{' expr ';' '}'
+			{ $$ = newBINOP(OP_HELEM, 0,
+					ref(newHVREF($1),OP_RV2HV),
+					jmaybe($3));
+			    PL_expect = XOPERATOR; }
+	|	term ARROW '(' ')'
+			{ $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
+				   newCVREF(0, scalar($1))); }
+	|	term ARROW '(' expr ')'
+			{ $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
+				   append_elem(OP_LIST, $4,
+				       newCVREF(0, scalar($1)))); }
+
+	|	subscripted '(' expr ')'
+			{ $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
+				   append_elem(OP_LIST, $3,
+					       newCVREF(0, scalar($1)))); }
+	|	subscripted '(' ')'
+			{ $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
+				   newCVREF(0, scalar($1))); }
+
+
+
 term	:	term ASSIGNOP term
 			{ $$ = newASSIGNOP(OPf_STACKED, $1, $2, $3); }
 	|	term POWOP term
@@ -442,9 +490,9 @@ term	:	term ASSIGNOP term
 			{ $$ = sawparens($2); }
 	|	'(' ')'
 			{ $$ = sawparens(newNULLLIST()); }
-	|	'[' expr ']'				%prec '('
+	|	'[' expr ']'
 			{ $$ = newANONLIST($2); }
-	|	'[' ']'					%prec '('
+	|	'[' ']'
 			{ $$ = newANONLIST(Nullop); }
 	|	HASHBRACK expr ';' '}'			%prec '('
 			{ $$ = newANONHASH($2); }
@@ -454,50 +502,27 @@ term	:	term ASSIGNOP term
 			{ $$ = newANONSUB($2, $3, $4); }
 	|	scalar	%prec '('
 			{ $$ = $1; }
-	|	star '{' expr ';' '}'
-			{ $$ = newBINOP(OP_GELEM, 0, $1, scalar($3)); }
 	|	star	%prec '('
 			{ $$ = $1; }
-	|	scalar '[' expr ']'	%prec '('
-			{ $$ = newBINOP(OP_AELEM, 0, oopsAV($1), scalar($3)); }
-	|	term ARROW '[' expr ']'	%prec '('
-			{ $$ = newBINOP(OP_AELEM, 0,
-					ref(newAVREF($1),OP_RV2AV),
-					scalar($4));}
-	|	term '[' expr ']'	%prec '('
-			{ assertref($1); $$ = newBINOP(OP_AELEM, 0,
-					ref(newAVREF($1),OP_RV2AV),
-					scalar($3));}
 	|	hsh 	%prec '('
 			{ $$ = $1; }
 	|	ary 	%prec '('
 			{ $$ = $1; }
 	|	arylen 	%prec '('
 			{ $$ = newUNOP(OP_AV2ARYLEN, 0, ref($1, OP_AV2ARYLEN));}
-	|	scalar '{' expr ';' '}'	%prec '('
-			{ $$ = newBINOP(OP_HELEM, 0, oopsHV($1), jmaybe($3));
-			    PL_expect = XOPERATOR; }
-	|	term ARROW '{' expr ';' '}'	%prec '('
-			{ $$ = newBINOP(OP_HELEM, 0,
-					ref(newHVREF($1),OP_RV2HV),
-					jmaybe($4));
-			    PL_expect = XOPERATOR; }
-	|	term '{' expr ';' '}'	%prec '('
-			{ assertref($1); $$ = newBINOP(OP_HELEM, 0,
-					ref(newHVREF($1),OP_RV2HV),
-					jmaybe($3));
-			    PL_expect = XOPERATOR; }
-	|	'(' expr ')' '[' expr ']'	%prec '('
+	|       subscripted
+			{ $$ = $1; }
+	|	'(' expr ')' '[' expr ']'
 			{ $$ = newSLICEOP(0, $5, $2); }
-	|	'(' ')' '[' expr ']'	%prec '('
+	|	'(' ')' '[' expr ']'
 			{ $$ = newSLICEOP(0, $4, Nullop); }
-	|	ary '[' expr ']'	%prec '('
+	|	ary '[' expr ']'
 			{ $$ = prepend_elem(OP_ASLICE,
 				newOP(OP_PUSHMARK, 0),
 				    newLISTOP(OP_ASLICE, 0,
 					list($3),
 					ref($1, OP_ASLICE))); }
-	|	ary '{' expr ';' '}'	%prec '('
+	|	ary '{' expr ';' '}'
 			{ $$ = prepend_elem(OP_HSLICE,
 				newOP(OP_PUSHMARK, 0),
 				    newLISTOP(OP_HSLICE, 0,
@@ -546,13 +571,6 @@ term	:	term ASSIGNOP term
 			    prepend_elem(OP_LIST,
 				$4,
 				scalar(newCVREF(0,scalar($2))))); dep();}
-	|	term ARROW '(' ')'	%prec '('
-			{ $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
-				   newCVREF(0, scalar($1))); }
-	|	term ARROW '(' expr ')'	%prec '('
-			{ $$ = newUNOP(OP_ENTERSUB, OPf_STACKED,
-				   append_elem(OP_LIST, $4,
-				       newCVREF(0, scalar($1)))); }
 	|	LOOPEX
 			{ $$ = newOP($1, OPf_SPECIAL);
 			    PL_hints |= HINT_BLOCK_SCOPE; }
@@ -588,9 +606,9 @@ term	:	term ASSIGNOP term
 	|	listop
 	;
 
-listexpr:	/* NULL */
+listexpr:	/* NULL */ %prec PREC_LOW
 			{ $$ = Nullop; }
-	|	argexpr
+	|	argexpr    %prec PREC_LOW
 			{ $$ = $1; }
 	;
 
@@ -636,7 +654,7 @@ star	:	'*' indirob
 
 indirob	:	WORD
 			{ $$ = scalar($1); }
-	|	scalar
+	|	scalar %prec PREC_LOW
 			{ $$ = scalar($1);  }
 	|	block
 			{ $$ = scope($1); }