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|
%token Tword Twords Tif Telse Tbang Tsubshell
%token Targs Tindex
%token Tbasic Tparen Tblock
%define parse.error verbose
%{
#include "rc.h"
int yylex(void);
void yyerror(const char *);
%}
/* operator precendence: lowest first */
%left Twhile Telse
%left '\n'
%left Tbang Tsubshell
%right '$' Tcount Tflat
%right Tindex
/* semantic types */
%union{
struct Tree *tree;
}
%type<tree> line cmds cmdsln body paren block ifbody assign;
%type<tree> cmd basic executable nonkeyword keyword word words wordsnl atom arg args;
%type<tree> Tbang Tsubshell Tindex;
%type<tree> Tword Tif Telse;
/* grammar */
%start rc
%%
rc:
/*empty*/ { return 0; }
| line '\n' { return compile($1); }
line:
cmd
| cmds line { $$ = maketree2(';', $1, $2); }
body:
cmd
| cmdsln body { $$ = maketree2(';', $1, $2); }
paren:
'(' body ')' { $$ = maketree1(Tparen, $2); }
block:
'{' body '}' { $$ = maketree1(Tblock, $2); }
cmds:
cmd ';'
| cmd '&' { $$ = maketree1('&', $1); }
cmdsln:
cmds
| cmd '\n'
ifbody:
cmd %prec Telse { $$ = maketree2(Tif, nil, $1); }
| block Telse nl cmd { $$ = maketree3(Tif, nil, $1, $2); }
assign:
executable '=' word { $$ = maketree2('=', $1, $3); }
cmd:
/* empty */ %prec Twhile { $$ = nil; }
| basic { $$ = maketree1(Tbasic, $1); }
| block
| assign cmd %prec Tbang { $$ = hangchild1($1, $2, 2); }
| Tif paren nl ifbody { $$ = hangchild1($2, $1, 0); }
| Tbang cmd { $$ = maketree1(Tbang, $2); }
| Tsubshell cmd { $$ = maketree1(Tsubshell, $2); }
basic:
executable
| basic word { $$ = maketree2(Targs, $1, $2); }
arg: word
args:
arg
| args arg { $$ = maketree2(Targs, $1, $2); }
atom:
nonkeyword
| keyword { $$ = maketree1(Tword, $1); }
word:
atom
| word '^' atom { $$ = maketree2('^', $1, $3); }
executable:
nonkeyword
| executable '^' atom { $$ = maketree2('^', $1, $3); }
nonkeyword:
Tword
| '$' atom { $$ = maketree1('$', $2); }
| '(' wordsnl ')' { $$ = $2; }
| Tcount atom { $$ = maketree1(Tcount, $2); }
| Tflat atom { $$ = maketree1(Tflat, $2); }
//| '`' block { $$ = maketree1('`', $2); }
keyword:
Tif|Telse|Tbang|Tsubshell
words:
/* empty */ { $$ = nil; }
| words word { $$ = maketree2(Twords, $1, $2); }
wordsnl:
/* empty */ { $$ = nil; }
| wordsnl '\n' /* empty */
| wordsnl word {$$ = (!$1) ? ((!$2) ? nil : $2) : ((!$2) ? $1 : maketree2(Twords, $1, $2)); }
nl:
/*empty*/
| nl '\n'
%%
|
