Allow nextterm specifier, nulltermish tokens.

perl6 · Oct 20, 2009 · 7451fb8 · 7451fb8
1 parent 7591d1c
commit 7451fb8
Show file tree

Hide file tree

Showing 3 changed files with 31 additions and 9 deletions.
diff --git a/src/NQP/Actions.pm b/src/NQP/Actions.pm
@@ -9,6 +9,7 @@ NQP::Grammar.O(':prec<u=>, :assoc<left>',  '%multiplicative');
 NQP::Grammar.O(':prec<t=>, :assoc<left>',  '%additive');
 NQP::Grammar.O(':prec<r=>, :assoc<list>',  '%concatenation'); 
 NQP::Grammar.O(':prec<i=>, :assoc<right>', '%assignment');
+NQP::Grammar.O(':prec<g=>, :assoc<list>, :nextterm<nulltermish>',  '%comma');
 
 method TOP($/) { make $<EXPR>.ast; }
 
@@ -30,3 +31,6 @@ method value($/) {
     make $past;
 }
 
+method nulltermish($/) {
+    make $<noun> ?? $<noun>.ast !! 0;
+}
diff --git a/src/NQP/Grammar.pm b/src/NQP/Grammar.pm
@@ -14,6 +14,7 @@ token infix:sym<+>  { $<sym>=['+']  <O('%additive      , :pirop<add>')> }
 token infix:sym<->  { $<sym>=['-']  <O('%additive      , :pirop<sub>')> }
 token infix:sym<=>  { $<sym>=['=']  <O('%assignment')> }
 token infix:sym<~>  { $<sym>=['~']  <O('%concatenation')> }
+token infix:sym<,>  { $<sym>=[',']  <O('%comma')> }
 
 token prefix:sym<-> { $<sym>=['-']  <O('%symbolic_unary')> }
 token prefix:sym<--> { $<sym>=['--'] <O('%autoincrement')> }
@@ -38,4 +39,7 @@ token quote:sym<" "> { <?["]>            <quote_EXPR: ':qq'> }
 token quote:sym<q>   { 'q'  <![(]> <.ws> <quote_EXPR: ':q'>  }
 token quote:sym<qq>  { 'qq' <![(]> <.ws> <quote_EXPR: ':qq'> }
 
-
+token nulltermish { 
+    | <OPER=noun=noun> 
+    | <?>
+}
diff --git a/src/cheats/hll-grammar.pir b/src/cheats/hll-grammar.pir
@@ -377,15 +377,22 @@ An operator precedence parser.
   term_loop:
     here = here.termish()
     unless here goto fail
-    termish = 'termish'
     .local pmc term
     term = here.'MATCH'()
     push termstack, term
 
     # interleave any prefix/postfix we might have found
-    .local pmc prefixish, postfixish
-    prefixish = term['prefixish']
-    postfixish = term['postfixish']
+    .local pmc termOPER, prefixish, postfixish
+    termOPER = term
+  termOPER_loop:
+    $I0 = exists termOPER['OPER']
+    unless $I0 goto termOPER_done
+    termOPER = termOPER['OPER']
+    goto termOPER_loop
+  termOPER_done:
+    prefixish = termOPER['prefixish']
+    postfixish = termOPER['postfixish']
+    if null prefixish goto prefix_done
 
   prepostfix_loop:
     unless prefixish goto prepostfix_done
@@ -423,6 +430,7 @@ An operator precedence parser.
     delete term['prefixish']
 
   postfix_loop:
+    if null postfixish goto postfix_done
     unless postfixish goto postfix_done
     $P0 = pop postfixish
     push opstack, $P0
@@ -437,13 +445,19 @@ An operator precedence parser.
     unless infixcur goto term_done
     infix = infixcur.'MATCH'()
 
+    .local pmc inO
+    $P0 = infix['OPER']
+    inO = $P0['O']
+    termish = inO['nextterm']
+    if termish goto have_termish
+    termish = 'termish'
+  have_termish:
+
     unless opstack goto reduce_done
     .local string inprec, inassoc, opprec
-    $P0 = infix['OPER']
-    $P0 = $P0['O']
-    inprec = $P0['prec']
-    inassoc = $P0['assoc']
+    inprec = inO['prec']
     unless inprec goto err_inprec
+    inassoc = inO['assoc']
 
   reduce_loop:
     unless opstack goto reduce_done