parser: Script for extended sablecc3 syntax

Move hacks from the Makefile to a new shell script (prescc.sh).
Propose a cleaner syntax with ~ and ! characters.
See doc in prescc.sh for details.

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/.gitignore b/.gitignore
index c400110..3a61ae7 100644 (file)
--- a/.gitignore
+++ b/.gitignore
@@ -9,8 +9,8 @@ doc/stdlib
 
 src/nitc
 src/nitc_?
-src/parser/nit.sablecc3
-src/parser/nit.sablecc3.dump
+src/parser/.nit.sablecc3
+src/parser/.nit.sablecc3.dump
 src/parser/parser_abs.patch
 src/parser/parser_nodes.nit.rej
 

diff --git a/src/parser/Makefile b/src/parser/Makefile
index 67b0272..262c6e0 100644 (file)
--- a/src/parser/Makefile
+++ b/src/parser/Makefile
@@ -1,6 +1,6 @@
 # This file is part of NIT ( http://www.nitlanguage.org ).
 #
-# Copyright 2008 Jean Privat <jean@pryen.org>
+# Copyright 2008-2009 Jean Privat <jean@pryen.org>
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -18,40 +18,19 @@ SABLECC=sablecc3
 
 all: parser.nit
 
-# first sed start from first line to line /*I*/ and remove /*.*/
-# second sed clones /*B*/ productions, substitute /*B*/ with no_bra and delete /*N*/ lines
-# third sed from line /*I*/ to last line and remove /*.*/
-nit.sablecc3: nit.sablecc3xx
-       @test -f nit.sablecc3 && chmod +w nit.sablecc3 || touch nit.sablecc3
-       @echo -n "// This file is autogenerated, no dot modify it" > nit.sablecc3.t
-       sed -n -e '1,/\/\*I\*\//{s/\/\*[BIN]\*\///g;p}' nit.sablecc3xx >> nit.sablecc3.t
-       sed -n -e '/\/\*B\*\//,/;/{s/\/\*B\*\//_nobra/g;/\/\*N\*\//d;p}' nit.sablecc3xx >> nit.sablecc3.t
-       sed -n -e '/\/\*I\*\//,$${s/\/\*[BIN]\*\///g;p}' nit.sablecc3xx >> nit.sablecc3.t
-       
-       > nit.sablecc3
-       sed -n -e '1,/\/\*I2\*\//{s/\/\*[BIN]2\*\///g;p}' nit.sablecc3.t >> nit.sablecc3
-       sed -n -e '/\/\*B2\*\//,/;/{s/\/\*B2\*\//_withelse/g;/\/\*N2\*\//d;p}' nit.sablecc3.t >> nit.sablecc3
-       sed -n -e '/\/\*I2\*\//,$${s/\/\*[BIN]2\*\///g;p}' nit.sablecc3.t >> nit.sablecc3
-       
-       cp nit.sablecc3 nit.sablecc3.t
-       > nit.sablecc3
-       sed -n -e '1,/\/\*I3\*\//{s/\/\*[BIN]3\*\///g;p}' nit.sablecc3.t >> nit.sablecc3
-       sed -n -e '/\/\*B3\*\//,/;/{s/\/\*B3\*\//_nopar/g;/\/\*N3\*\//d;p}' nit.sablecc3.t >> nit.sablecc3
-       sed -n -e '/\/\*I3\*\//,$${s/\/\*[BIN]3\*\///g;p}' nit.sablecc3.t >> nit.sablecc3
-       
-       rm nit.sablecc3.t
-       @sed -i -e '{s/\/\/#.*//}' nit.sablecc3
-       @chmod -w nit.sablecc3
+# Preprocess the extended sablecc gramar
+.nit.sablecc3: nit.sablecc3xx
+       ./prescc.sh $< $@
 
 # Note that parser_nodes is automatically synced with the grammar
-parser.nit: nit.sablecc3 xss/*.xss
+parser.nit: .nit.sablecc3 xss/*.xss
        cp parser_abs.nit parser_abs.nit.bak || true
-       ${SABLECC} -c nit.sablecc3.dump -t xss/main.xss -p usermodule parser_nodes nit.sablecc3
+       ${SABLECC} -c .nit.sablecc3.dump -t xss/main.xss -p usermodule parser_nodes .nit.sablecc3
        diff -u parser_abs.nit.bak parser_abs.nit > parser_abs.patch || true
        patch parser_nodes.nit < parser_abs.patch || true
 
 clean:
-       rm -f -- nit.sablecc3 nit.sablecc3.dump parser_abs.patch || true
+       rm -f -- .nit.sablecc3 .nit.sablecc3.dump parser_abs.patch || true
 
 dist-clean: clean
        rm -f -- parser.nit parser_abs.nit parser_abs.patch parser_abs.nit.bak parser_prod.nit parser_tables.nit lexer.nit || true

diff --git a/src/parser/nit.sablecc3xx b/src/parser/nit.sablecc3xx
index 3cfcf96..93be63a 100644 (file)
--- a/src/parser/nit.sablecc3xx
+++ b/src/parser/nit.sablecc3xx
@@ -1,7 +1,7 @@
 
 /* This file is part of NIT ( http://www.nitlanguage.org ).
  *
- * Copyright 2008 Jean Privat <jean@pryen.org>
+ * Copyright 2008-2009 Jean Privat <jean@pryen.org>
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -283,11 +283,10 @@ closure_decl
        ;
 
 /* TYPES *********************************************************************/
-type/*B3*//*B*/ {-> type}
+type~nopar~nobra {-> type}
        = {simple} classid {-> New type(classid, [])}
-/*N*/  | {generic} classid obra no types [n2]:no cbra {-> New type(classid, [types.type])}
+!nobra | {generic} classid obra no types [n2]:no cbra {-> New type(classid, [types.type])}
        ;
-/*E*/
 types {-> type*} 
        = type types_tail* {-> [type, types_tail.type]};
 types_tail {-> type}
@@ -296,8 +295,8 @@ typing {-> type}
        = column no type {-> type};
 
 /* STATMENTS *****************************************************************/
-stmtso/*B2*/ {-> expr?}
-       = {oneline} stmt/*B2*/ {-> stmt/*B2*/.expr}
+stmtso~withelse {-> expr?}
+       = {oneline} stmt~withelse {-> stmt~withelse.expr}
        | {block} n stmts [n2]:n kwend {-> stmts.expr}
        | {emptyblock} n kwend {-> New expr.block([])}
        | {emptyoneline} kwend {-> New expr.block([])}
@@ -306,31 +305,31 @@ stmts {-> expr}
        = stmt stmts_tail* {-> New expr.block([stmt.expr, stmts_tail.expr])};
 stmts_tail {-> expr}
        = n stmt {-> stmt.expr};
-stmt/*B2*/ {-> expr}
-       = {vardecl} vardecl/*B2*/ {-> vardecl/*B2*/.expr}
-       | {assign} assignment/*B2*/ {-> assignment/*B2*/.expr}
-       | {return} kwreturn expr_final/*B2*/? {-> New expr.return(kwreturn, expr_final/*B2*/.expr)}
-       | {break} kwbreak expr_final/*B2*/? {-> New expr.break(kwbreak, expr_final/*B2*/.expr)}
+stmt~withelse {-> expr}
+       = {vardecl} vardecl~withelse {-> vardecl~withelse.expr}
+       | {assign} assignment~withelse {-> assignment~withelse.expr}
+       | {return} kwreturn expr_final~withelse? {-> New expr.return(kwreturn, expr_final~withelse.expr)}
+       | {break} kwbreak expr_final~withelse? {-> New expr.break(kwbreak, expr_final~withelse.expr)}
        | {abort} kwabort {-> New expr.abort(kwabort)}
-       | {continue} kwcontinue expr_final/*B2*/? {-> New expr.continue(kwcontinue, expr_final/*B2*/.expr)}
-       | {do} do/*B2*/ {-> do/*B2*/.expr}
-       | {if} if/*B2*/ {-> if/*B2*/.expr}
-       | {while} while/*B2*/ {-> while/*B2*/.expr}
-       | {for} for/*B2*/ {-> for/*B2*/.expr}
-       | {assert} assert/*B2*/ {-> assert/*B2*/.expr}
+       | {continue} kwcontinue expr_final~withelse? {-> New expr.continue(kwcontinue, expr_final~withelse.expr)}
+       | {do} do~withelse {-> do~withelse.expr}
+       | {if} if~withelse {-> if~withelse.expr}
+       | {while} while~withelse {-> while~withelse.expr}
+       | {for} for~withelse {-> for~withelse.expr}
+       | {assert} assert~withelse {-> assert~withelse.expr}
 //     | {expr} expr {-> expr.expr}
-       | {call} recv id args_nopar closure_defs/*B2*/? {-> New expr.call(recv.expr, id, [args_nopar.expr], [closure_defs/*B2*/.closure_def])}
+       | {call} recv id args_nopar closure_defs~withelse? {-> New expr.call(recv.expr, id, [args_nopar.expr], [closure_defs~withelse.closure_def])}
        | {super} qualified? kwsuper args_nopar {-> New expr.super(qualified, kwsuper, [args_nopar.expr])}
        | {init} recv kwinit args_nopar {-> New expr.init(recv.expr, kwinit, [args_nopar.expr])}
        ;
 
-closure_defs/*B2*/ {-> closure_def*}
-       = {one} closure_def_last/*B2*/ {-> [closure_def_last/*B2*/.closure_def]}
-       | closure_def closure_defs/*B2*/ {-> [closure_def, closure_defs/*B2*/.closure_def]}
+closure_defs~withelse {-> closure_def*}
+       = {one} closure_def_last~withelse {-> [closure_def_last~withelse.closure_def]}
+       | closure_def closure_defs~withelse {-> [closure_def, closure_defs~withelse.closure_def]}
        ;
 
-closure_def_last/*B2*/ {-> closure_def}
-       = kwwith idlist? kwdo stmtso/*B2*/ {-> New closure_def(kwwith, [idlist.id], kwdo, stmtso/*B2*/.expr)}
+closure_def_last~withelse {-> closure_def}
+       = kwwith idlist? kwdo stmtso~withelse {-> New closure_def(kwwith, [idlist.id], kwdo, stmtso~withelse.expr)}
        ;
 
 closure_def {-> closure_def}
@@ -338,122 +337,122 @@ closure_def {-> closure_def}
        | {empty} kwwith idlist? kwdo n {-> New closure_def(kwwith, [idlist.id], kwdo, Null)}
        ;
 
-vardecl/*B2*/{-> expr}
+vardecl~withelse{-> expr}
        = kwvar id typing? {-> New expr.vardecl(kwvar, id, typing.type, Null, Null)}
-       | {assign} kwvar id typing? assign no expr_final/*B2*/ {-> New expr.vardecl(kwvar, id, typing.type, assign, expr_final/*B2*/.expr)}
+       | {assign} kwvar id typing? assign no expr_final~withelse {-> New expr.vardecl(kwvar, id, typing.type, assign, expr_final~withelse.expr)}
        ;
 
-assignment/*B2*/ {-> expr}
-       = {attr} recv attrid assign expr_final/*B2*/ {-> New expr.attr_assign(recv.expr, attrid, assign, expr_final/*B2*/.expr)}
-       | {call} recv id args assign expr_final/*B2*/ {-> New expr.call_assign(recv.expr, id, [args.expr], assign,  expr_final/*B2*/.expr)}
-       | {bra} expr_atom braargs assign expr_final/*B2*/ {-> New expr.bra_assign(expr_atom.expr, [braargs.expr], assign,  expr_final/*B2*/.expr)}
-       | {attr_re} recv attrid assign_op expr_final/*B2*/ {-> New expr.attr_reassign(recv.expr, attrid, assign_op,  expr_final/*B2*/.expr)}
-       | {call_re} recv id args assign_op expr_final/*B2*/ {-> New expr.call_reassign(recv.expr, id, [args.expr], assign_op,  expr_final/*B2*/.expr)}
-       | {bra_re} expr_atom braargs assign_op expr_final/*B2*/ {-> New expr.bra_reassign(expr_atom.expr, [braargs.expr], assign_op,  expr_final/*B2*/.expr)}
+assignment~withelse {-> expr}
+       = {attr} recv attrid assign expr_final~withelse {-> New expr.attr_assign(recv.expr, attrid, assign, expr_final~withelse.expr)}
+       | {call} recv id args assign expr_final~withelse {-> New expr.call_assign(recv.expr, id, [args.expr], assign,  expr_final~withelse.expr)}
+       | {bra} expr_atom braargs assign expr_final~withelse {-> New expr.bra_assign(expr_atom.expr, [braargs.expr], assign,  expr_final~withelse.expr)}
+       | {attr_re} recv attrid assign_op expr_final~withelse {-> New expr.attr_reassign(recv.expr, attrid, assign_op,  expr_final~withelse.expr)}
+       | {call_re} recv id args assign_op expr_final~withelse {-> New expr.call_reassign(recv.expr, id, [args.expr], assign_op,  expr_final~withelse.expr)}
+       | {bra_re} expr_atom braargs assign_op expr_final~withelse {-> New expr.bra_reassign(expr_atom.expr, [braargs.expr], assign_op,  expr_final~withelse.expr)}
        ;
 assign_op
        = {plus} pluseq
        | {minus} minuseq
        ;
 
-do/*B2*/ {-> expr}
-       = kwdo stmtso/*B2*/ {-> New expr.do(kwdo, stmtso/*B2*/.expr)}
+do~withelse {-> expr}
+       = kwdo stmtso~withelse {-> New expr.do(kwdo, stmtso~withelse.expr)}
        ;
 
-if/*B2*/ {-> expr}
-       = {onelineelse} kwif no expr [n2]:no kwthen stmt_withelse kwelse stmtso/*B2*/ {-> New expr.if(kwif, expr, stmt_withelse.expr, stmtso/*B2*/.expr)}
-/*N2*/ | {oneline} kwif no expr [n2]:no kwthen stmt {-> New expr.if(kwif, expr, stmt.expr, Null)}
-/*N2*/ | {block} kwif no expr [n2]:no kwthen [n3]:n stmts [n4]:n elsepartblock {-> New expr.if(kwif, expr, stmts.expr, elsepartblock.expr)}
-/*N2*/ | {emptyblock} kwif no expr [n2]:no kwthen [n3]:n? elsepartblock {-> New expr.if(kwif, expr, Null, elsepartblock.expr)}
+if~withelse {-> expr}
+       = {onelineelse} kwif no expr [n2]:no kwthen stmt_withelse kwelse stmtso~withelse {-> New expr.if(kwif, expr, stmt_withelse.expr, stmtso~withelse.expr)}
+!withelse      | {oneline} kwif no expr [n2]:no kwthen stmt {-> New expr.if(kwif, expr, stmt.expr, Null)}
+!withelse      | {block} kwif no expr [n2]:no kwthen [n3]:n stmts [n4]:n elsepartblock {-> New expr.if(kwif, expr, stmts.expr, elsepartblock.expr)}
+!withelse      | {emptyblock} kwif no expr [n2]:no kwthen [n3]:n? elsepartblock {-> New expr.if(kwif, expr, Null, elsepartblock.expr)}
        ;
 elsepartblock {-> expr?}
        = {else} kwelse stmtso {-> stmtso.expr}
        | {empty} kwend {-> Null}
        ;
 
-while/*B2*/ {-> expr}
-       = kwwhile no expr [n2]:no kwdo stmtso/*B2*/ {-> New expr.while(kwwhile, expr, kwdo, stmtso/*B2*/.expr)};
+while~withelse {-> expr}
+       = kwwhile no expr [n2]:no kwdo stmtso~withelse {-> New expr.while(kwwhile, expr, kwdo, stmtso~withelse.expr)};
  
-for/*B2*/ {-> expr}
-       = for_vardecl [n4]:no kwdo stmtso/*B2*/ {-> New expr.for(for_vardecl.expr, kwdo, stmtso/*B2*/.expr)};
+for~withelse {-> expr}
+       = for_vardecl [n4]:no kwdo stmtso~withelse {-> New expr.for(for_vardecl.expr, kwdo, stmtso~withelse.expr)};
 for_vardecl {-> expr}
        = kwfor no id [n2]:no kwin [n3]:no expr {-> New expr.for_vardecl(kwfor, id, expr)};
 
-assert/*B2*/ {-> expr}
-       = kwassert assertid? expr_final/*B2*/ {-> New expr.assert(kwassert, assertid.id, expr_final/*B2*/.expr)};
+assert~withelse {-> expr}
+       = kwassert assertid? expr_final~withelse {-> New expr.assert(kwassert, assertid.id, expr_final~withelse.expr)};
 assertid {-> id}
        = id column {-> id};
 
 /* EXPRESSIONS ***************************************************************/
-expr_final/*B3*//*B2*//*B*/ {-> expr}
-       = expr/*B3*//*B*/ {-> expr/*B3*//*B*/.expr}
-       | {closure_call} recv/*B*/ id args closure_defs/*B2*/ {-> New expr.call(recv/*B*/.expr, id, [args.expr], [closure_defs/*B2*/.closure_def])}
-/*N*//*N3*/    | {closure_bra} expr_atom braargs closure_defs/*B2*/ {-> New expr.bra(expr_atom.expr, [braargs.expr], [closure_defs/*B2*/.closure_def])}
+expr_final~nopar~withelse~nobra {-> expr}
+       = expr~nopar~nobra {-> expr~nopar~nobra.expr}
+       | {closure_call} recv~nobra id args closure_defs~withelse {-> New expr.call(recv~nobra.expr, id, [args.expr], [closure_defs~withelse.closure_def])}
+!nobra!nopar   | {closure_bra} expr_atom braargs closure_defs~withelse {-> New expr.bra(expr_atom.expr, [braargs.expr], [closure_defs~withelse.closure_def])}
        ;
 
-expr/*B3*//*B*/ {-> expr}
-       = expr_and/*B3*//*B*/ {-> expr_and/*B3*//*B*/.expr}
-       | {ifexpr} kwif [n1]:no expr [n2]:no kwthen [n3]:no [then]:expr [n4]:no kwelse [n5]:no [else]:expr/*B3*//*B*/ {-> New expr.ifexpr(kwif, expr, kwthen, then, kwelse, else.expr)}
+expr~nopar~nobra {-> expr}
+       = expr_and~nopar~nobra {-> expr_and~nopar~nobra.expr}
+       | {ifexpr} kwif [n1]:no expr [n2]:no kwthen [n3]:no [then]:expr [n4]:no kwelse [n5]:no [else]:expr~nopar~nobra {-> New expr.ifexpr(kwif, expr, kwthen, then, kwelse, else.expr)}
        ;
 
-expr_and/*B3*//*B*/ {-> expr}
-       = expr_not/*B3*//*B*/ {-> expr_not/*B3*//*B*/.expr}
-       | {or} expr_and/*B3*//*B*/ kwor no expr_not/*B3*//*B*/ {-> New expr.or(expr_and/*B3*//*B*/.expr, expr_not/*B3*//*B*/.expr)}
-       | {and} expr_and/*B3*//*B*/ kwand no expr_not/*B3*//*B*/ {-> New expr.and(expr_and/*B3*//*B*/.expr, expr_not/*B3*//*B*/.expr)}
+expr_and~nopar~nobra {-> expr}
+       = expr_not~nopar~nobra {-> expr_not~nopar~nobra.expr}
+       | {or} expr_and~nopar~nobra kwor no expr_not~nopar~nobra {-> New expr.or(expr_and~nopar~nobra.expr, expr_not~nopar~nobra.expr)}
+       | {and} expr_and~nopar~nobra kwand no expr_not~nopar~nobra {-> New expr.and(expr_and~nopar~nobra.expr, expr_not~nopar~nobra.expr)}
        ;
 
-expr_not/*B3*//*B*/ {-> expr}
-       = expr_eq/*B3*//*B*/ {-> expr_eq/*B3*//*B*/.expr}
-       | {not} kwnot no expr_not/*B3*//*B*/ {-> New expr.not(kwnot, expr_not/*B3*//*B*/.expr)}
+expr_not~nopar~nobra {-> expr}
+       = expr_eq~nopar~nobra {-> expr_eq~nopar~nobra.expr}
+       | {not} kwnot no expr_not~nopar~nobra {-> New expr.not(kwnot, expr_not~nopar~nobra.expr)}
        ;
 
-expr_eq/*B3*//*B*/ {-> expr}
-       = expr_add/*B3*//*B*/ {-> expr_add/*B3*//*B*/.expr}
-       | {eq} expr_add/*B3*//*B*/ eq no [expr2]:expr_add/*B3*//*B*/ {-> New expr.eq(expr_add/*B3*//*B*/.expr, expr2.expr)}
-       | {ee} expr_add/*B3*//*B*/ kwis no [expr2]:expr_add/*B3*//*B*/ {-> New expr.ee(expr_add/*B3*//*B*/.expr, expr2.expr)}
-       | {ne} expr_add/*B3*//*B*/ ne no [expr2]:expr_add/*B3*//*B*/ {-> New expr.ne(expr_add/*B3*//*B*/.expr, expr2.expr)}
-       | {lt} expr_add/*B3*//*B*/ lt no [expr2]:expr_add/*B3*//*B*/ {-> New expr.lt(expr_add/*B3*//*B*/.expr, expr2.expr)}
-       | {le} expr_add/*B3*//*B*/ le no [expr2]:expr_add/*B3*//*B*/ {-> New expr.le(expr_add/*B3*//*B*/.expr, expr2.expr)}
-       | {gt} expr_add/*B3*//*B*/ gt no [expr2]:expr_add/*B3*//*B*/ {-> New expr.gt(expr_add/*B3*//*B*/.expr, expr2.expr)}
-       | {ge} expr_add/*B3*//*B*/ ge no [expr2]:expr_add/*B3*//*B*/ {-> New expr.ge(expr_add/*B3*//*B*/.expr, expr2.expr)}
-       | {starship} expr_add/*B3*//*B*/ starship no [expr2]:expr_add/*B3*//*B*/ {-> New expr.starship(expr_add/*B3*//*B*/.expr, expr2.expr)}
-       | {isa} expr_add/*B3*//*B*/ kwisa no type/*B3*//*B*/ {-> New expr.isa(expr_add/*B3*//*B*/.expr, type/*B3*//*B*/.type)}
+expr_eq~nopar~nobra {-> expr}
+       = expr_add~nopar~nobra {-> expr_add~nopar~nobra.expr}
+       | {eq} expr_add~nopar~nobra eq no [expr2]:expr_add~nopar~nobra {-> New expr.eq(expr_add~nopar~nobra.expr, expr2.expr)}
+       | {ee} expr_add~nopar~nobra kwis no [expr2]:expr_add~nopar~nobra {-> New expr.ee(expr_add~nopar~nobra.expr, expr2.expr)}
+       | {ne} expr_add~nopar~nobra ne no [expr2]:expr_add~nopar~nobra {-> New expr.ne(expr_add~nopar~nobra.expr, expr2.expr)}
+       | {lt} expr_add~nopar~nobra lt no [expr2]:expr_add~nopar~nobra {-> New expr.lt(expr_add~nopar~nobra.expr, expr2.expr)}
+       | {le} expr_add~nopar~nobra le no [expr2]:expr_add~nopar~nobra {-> New expr.le(expr_add~nopar~nobra.expr, expr2.expr)}
+       | {gt} expr_add~nopar~nobra gt no [expr2]:expr_add~nopar~nobra {-> New expr.gt(expr_add~nopar~nobra.expr, expr2.expr)}
+       | {ge} expr_add~nopar~nobra ge no [expr2]:expr_add~nopar~nobra {-> New expr.ge(expr_add~nopar~nobra.expr, expr2.expr)}
+       | {starship} expr_add~nopar~nobra starship no [expr2]:expr_add~nopar~nobra {-> New expr.starship(expr_add~nopar~nobra.expr, expr2.expr)}
+       | {isa} expr_add~nopar~nobra kwisa no type~nopar~nobra {-> New expr.isa(expr_add~nopar~nobra.expr, type~nopar~nobra.type)}
        ;
 
-expr_add/*B3*//*B*/ {-> expr}
-       =  expr_mul/*B3*//*B*/ {-> expr_mul/*B3*//*B*/.expr}
-       | {plus} expr_add/*B3*//*B*/ plus no [expr2]:expr_mul/*B3*//*B*/ {-> New expr.plus(expr_add/*B3*//*B*/.expr, expr2.expr)}
-       | {minus} expr_add/*B3*//*B*/ minus no [expr2]:expr_mul/*B3*//*B*/ {-> New expr.minus(expr_add/*B3*//*B*/.expr, expr2.expr)}
+expr_add~nopar~nobra {-> expr}
+       =  expr_mul~nopar~nobra {-> expr_mul~nopar~nobra.expr}
+       | {plus} expr_add~nopar~nobra plus no [expr2]:expr_mul~nopar~nobra {-> New expr.plus(expr_add~nopar~nobra.expr, expr2.expr)}
+       | {minus} expr_add~nopar~nobra minus no [expr2]:expr_mul~nopar~nobra {-> New expr.minus(expr_add~nopar~nobra.expr, expr2.expr)}
        ;
 
-expr_mul/*B3*//*B*/ {-> expr}
-       = expr_minus/*B3*//*B*/ {-> expr_minus/*B3*//*B*/.expr}
-       | {star} expr_mul/*B3*//*B*/ star no [expr2]:expr_minus/*B3*//*B*/ {-> New expr.star(expr_mul/*B3*//*B*/.expr, expr2.expr)}
-       | {slash} expr_mul/*B3*//*B*/ slash no [expr2]:expr_minus/*B3*//*B*/ {-> New expr.slash(expr_mul/*B3*//*B*/.expr, expr2.expr)}
-       | {percent} expr_mul/*B3*//*B*/ percent no [expr2]:expr_minus/*B3*//*B*/ {-> New expr.percent(expr_mul/*B3*//*B*/.expr, expr2.expr)}
+expr_mul~nopar~nobra {-> expr}
+       = expr_minus~nopar~nobra {-> expr_minus~nopar~nobra.expr}
+       | {star} expr_mul~nopar~nobra star no [expr2]:expr_minus~nopar~nobra {-> New expr.star(expr_mul~nopar~nobra.expr, expr2.expr)}
+       | {slash} expr_mul~nopar~nobra slash no [expr2]:expr_minus~nopar~nobra {-> New expr.slash(expr_mul~nopar~nobra.expr, expr2.expr)}
+       | {percent} expr_mul~nopar~nobra percent no [expr2]:expr_minus~nopar~nobra {-> New expr.percent(expr_mul~nopar~nobra.expr, expr2.expr)}
        ;
 
-expr_minus/*B3*//*B*/ {-> expr}
-       = expr_new/*B3*//*B*/ {-> expr_new/*B3*//*B*/.expr}
-       | {minus} minus no expr_minus/*B3*//*B*/ {-> New expr.uminus(minus, expr_minus/*B3*//*B*/.expr)}
-       | {once} kwonce no expr_minus/*B3*//*B*/ {-> New expr.once(kwonce, expr_minus/*B3*//*B*/.expr)}
+expr_minus~nopar~nobra {-> expr}
+       = expr_new~nopar~nobra {-> expr_new~nopar~nobra.expr}
+       | {minus} minus no expr_minus~nopar~nobra {-> New expr.uminus(minus, expr_minus~nopar~nobra.expr)}
+       | {once} kwonce no expr_minus~nopar~nobra {-> New expr.once(kwonce, expr_minus~nopar~nobra.expr)}
        ;
 
-expr_new/*B3*//*B*/ {-> expr}
-       = expr_atom/*B3*//*B*/ {-> expr_atom/*B3*//*B*/.expr}
-       | {new} kwnew no type/*B3*//*B*/ args {-> New expr.new(kwnew, type/*B3*//*B*/.type, Null, [args.expr])}
+expr_new~nopar~nobra {-> expr}
+       = expr_atom~nopar~nobra {-> expr_atom~nopar~nobra.expr}
+       | {new} kwnew no type~nopar~nobra args {-> New expr.new(kwnew, type~nopar~nobra.type, Null, [args.expr])}
        ;
 
-expr_atom/*B3*//*B*/ {-> expr}
-       = {attr} recv/*B3*//*B*/ attrid {-> New expr.attr(recv/*B3*//*B*/.expr, attrid)}
-       | {call} recv/*B3*//*B*/ id args {-> New expr.call(recv/*B3*//*B*/.expr, id, [args.expr], [])}
+expr_atom~nopar~nobra {-> expr}
+       = {attr} recv~nopar~nobra attrid {-> New expr.attr(recv~nopar~nobra.expr, attrid)}
+       | {call} recv~nopar~nobra id args {-> New expr.call(recv~nopar~nobra.expr, id, [args.expr], [])}
        | {super} qualified? kwsuper args {-> New expr.super(qualified, kwsuper, [args.expr])}
-       | {init} recv/*B3*//*B*/ kwinit args {-> New expr.init(recv/*B3*//*B*/.expr, kwinit, [args.expr])}
-/*N*//*N3*/    | {bra} expr_atom braargs {-> New expr.bra(expr_atom.expr, [braargs.expr], [])}
-       | {new} kwnew no type/*B3*//*B*/ dot [n2]:no id args {-> New expr.new(kwnew, type/*B3*//*B*/.type, id, [args.expr])}
-/*N*//*N3*/    | {range} obra no expr [n2]:no dotdot [n3]:no [expr2]:expr_nobra [n4]:no cbra {-> New expr.crange(expr, expr2.expr)}
-/*N*//*N3*/    | {orange} obra no expr [n2]:no dotdot [n3]:no [expr2]:expr_nobra [n4]:no [cbra]:obra  {-> New expr.orange(expr, expr2.expr)}
-/*N*//*N3*/    | {array} braargs {-> New expr.array([braargs.expr])}
+       | {init} recv~nopar~nobra kwinit args {-> New expr.init(recv~nopar~nobra.expr, kwinit, [args.expr])}
+!nobra!nopar   | {bra} expr_atom braargs {-> New expr.bra(expr_atom.expr, [braargs.expr], [])}
+       | {new} kwnew no type~nopar~nobra dot [n2]:no id args {-> New expr.new(kwnew, type~nopar~nobra.type, id, [args.expr])}
+!nobra!nopar   | {range} obra no expr [n2]:no dotdot [n3]:no [expr2]:expr_nobra [n4]:no cbra {-> New expr.crange(expr, expr2.expr)}
+!nobra!nopar   | {orange} obra no expr [n2]:no dotdot [n3]:no [expr2]:expr_nobra [n4]:no [cbra]:obra  {-> New expr.orange(expr, expr2.expr)}
+!nobra!nopar   | {array} braargs {-> New expr.array([braargs.expr])}
        | {self} kwself {-> New expr.self(kwself)}
        | {true} kwtrue {-> New expr.true(kwtrue)}
        | {false} kwfalse {-> New expr.false(kwfalse)}
@@ -463,8 +462,8 @@ expr_atom/*B3*//*B*/ {-> expr}
        | {char} char  {-> New expr.char(char)}
        | {string} string  {-> New expr.string(string)}
        | {superstring} superstring  {-> superstring.expr}
-/*N3*/ | {par} opar expr cpar {-> expr}
-        | {as_cast} expr_atom/*B3*//*B*/ dot no kwas [n2]:no opar [n3]:no type [n4]:no cpar {-> New expr.as_cast(expr_atom/*B3*//*B*/.expr, kwas, type)}
+!nopar | {par} opar expr cpar {-> expr}
+        | {as_cast} expr_atom~nopar~nobra dot no kwas [n2]:no opar [n3]:no type [n4]:no cpar {-> New expr.as_cast(expr_atom~nopar~nobra.expr, kwas, type)}
        ;
 
 superstring {-> expr} 
@@ -482,8 +481,8 @@ superstring_end {-> expr}
 
 /* MISC **********************************************************************/
 
-recv/*B3*//*B*/ {-> expr}
-       = expr_atom/*B3*//*B*/ dot no {-> expr_atom/*B3*//*B*/.expr}
+recv~nopar~nobra {-> expr}
+       = expr_atom~nopar~nobra dot no {-> expr_atom~nopar~nobra.expr}
        | {implicit} {-> New expr.implicit_self()}
        ;
 
@@ -531,15 +530,6 @@ n2
        | {b} eol+
        ;
 
-/* EXPR NO BRACKETS **********************************************************/
-/* since there is no shift/reduce conflict handling in sablecc, the following
- * is a duplication of previous productions minus some alternative where '['
- * are not protected. */
-
-/*I*/
-/*I2*/
-/*I3*/
-
 /*****************************************************************************/
 Abstract Syntax Tree
 /*****************************************************************************/

diff --git a/src/parser/prescc.sh b/src/parser/prescc.sh
new file mode 100755 (executable)
index 0000000..fba7063
--- /dev/null
+++ b/src/parser/prescc.sh
@@ -0,0 +1,76 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Copyright 2009 Jean Privat <jean@pryen.org>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# prescc, a Sablecc preprocessor.
+#
+# Synopsis
+#
+#   Extends a sablecc grammar with parametrized productions.
+#
+# Description
+#
+#   A production named foo~bar~baz semantically correspond to a production foo with two boolean parameters bar and baz
+#   In fact foo is a family of 4 distinct productions: foo, foo_bar, foo_baz and foo_bar_baz
+#   In a parametrized production with a parameter ~xxx:
+#    * parameters (~xxx) are substituted with _xxx if the parameter is true and removed if the parameter is false
+#    * guarded alternatives (!xxx) are disabled if the parameter is true
+#
+# Limitations
+#
+#   prescc is badly implemented with shell, sed and perl and is not robust.
+#   Users must remember the following:
+#    * parametrized productions MUST be terminated with a line containing only a single semicolon (;)
+#    * parameters (~) and guards (!) in alternatives MUST correspond to a parameter of the enclosing production
+#    * if required, names in transformations MUST contain the full invocation name (with all parameters)
+#        foo bar_x~y~z_t baz {-> New p(foo, bar_x~y~z_t.q)}
+#    * guards do not understand grammar, they just remove the whole line
+#    * The AST MUST start with a line containing only "Abstract Syntax Tree"
+#
+# Example of the dangling else implementation:
+#
+#   stmt~withelse =
+#                'if' expr 'then' stmt_withelse 'else' stmt~withelse |
+#     !withelse  'if' expr 'then' stmt |
+#                nop
+#                ;
+
+
+case $# in
+       2);;
+       *) echo "Usage: prescc infile outfile"; exit
+esac
+
+
+infile=$1
+outfile=$2
+tmpfile=`mktemp "$2.XXXXXX"`
+
+echo -n "/* This file is autogenerated, do not modify it */" > "$outfile"
+cat "$infile" >> "$outfile"
+
+# The perl code is used to list all the available parameters in the extended grammar
+for token in `perl -ne 'if (/\~(\w+)/ && !$found{$1}) {print "$1\n"; $found{$1}=1}' "$infile"`
+do
+       echo "Parameter ~$token"
+       # first, sed starts from first line to the AST line and removes ~xxx and !xxx
+       sed -n -e "1,/^Abstract Syntax Tree/{/^Abstract Syntax Tree/b;s/[\~!]$token//g;p}" "$outfile" > "$tmpfile"
+       # second, sed clones ~xxx parametrized productions, substitute ~xxx with _xxx and delete !xxx lines
+       sed -n -e "/\~$token/,/;/{s/\~$token/_$token/g;/!$token/d;p}" "$outfile" >> "$tmpfile"
+       # third, sed continues fron AST line to last line and remove ~xxx and !xxx
+       sed -n -e "/^Abstract Syntax Tree/,\${s/[\~!]$token//g;p}" "$outfile" >> "$tmpfile"
+       mv "$tmpfile" "$outfile"
+done
+