1 files changed, 147 insertions, 0 deletions
diff --git a/src/cmd/rc/syntax.y b/src/cmd/rc/syntax.y
new file mode 100644
index 0000000..0bdc776
--- /dev/null
+++ b/src/cmd/rc/syntax.y
@@ -0,0 +1,147 @@
+%token Tfor Tin Twhile Tif Telse Tswitch Tcase Tcasebody Ttwiddle Tbang Tsubshell Tfunc
+%token Tredir Tdup Tpipe Tindex
+%token Tbasic Targs Tword Twords Tparen Tblock
+
+%define parse.error verbose
+
+%{
+    #include "rc.h"
+
+    int  yylex(void);
+    void yyerror(const char *);
+%}
+
+/* operator precendence: lowest first */
+%left Tif Tfor Tswitch Tcase ')' Twhile Telse
+%left Tandand Toror '\n'
+%left Tbang Tsubshell
+%left Tpipe;
+%left '^';
+%right '$' Tcount Tjoin
+%left Tindex
+
+/* semantic types */
+%union{
+    struct Tree *tree;
+}
+%type<tree> line cmds cmdsln body paren block ifbody casebody case assign epilog redir;
+%type<tree> cmd basic executable nonkeyword keyword word words wordsnl atom;
+%type<tree> Tfor Tin Twhile Tif Telse Tswitch Tcase Ttwiddle Tbang Tsubshell Tfunc;
+%type<tree> Tword Tredir Tpipe Tdup;
+
+/* 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 { $$ = maketree3(Tif, nil, $1, $2); }
+
+case:
+  Tcase words ';'    { $$ = hangchild1($1, $2, 0); }
+| Tcase words '\n'   { $$ = hangchild1($1, $2, 0); }
+
+casebody:
+  cmd                { $$ = maketree2(Tcasebody, $1, nil); }
+| case casebody      { $$ = maketree2(Tcasebody, $1, $2); }
+| cmdsln casebody    { $$ = maketree2(Tcasebody, $1, $2); }
+
+assign:
+    executable '=' word { $$ = maketree2('=', $1, $3); }
+
+redir:
+  Tdup
+| Tredir word              { $$ = hangchild1($1, $2, 0); }
+
+epilog:
+/* empty */     { $$ = nil; }
+| redir epilog  { $$ = hangchild1($1, $2, 1); }
+
+cmd:
+/* empty */  %prec Twhile                  { $$ = nil; }
+| basic                                    { $$ = maketree1(Tbasic, $1); }
+| block epilog                             { $$ = hangepilog($1, $2); }
+| cmd Tpipe nl cmd                         { $$ = hangchild2($2, $1, 0, $4, 1); }
+| cmd Tandand nl cmd                       { $$ = maketree2(Tandand, $1, $4); }
+| cmd Toror nl cmd                         { $$ = maketree2(Toror, $1, $4); }
+| redir  cmd %prec Tbang                   { $$ = hangchild1($1, $2, 1); }
+| assign cmd %prec Tbang                   { $$ = hangchild1($1, $2, 2); }
+| Tbang cmd                                { $$ = maketree1(Tbang, $2); }
+| Tsubshell cmd                            { $$ = maketree1(Tsubshell, $2); }
+| Tfor '(' word ')' nl cmd                 { $$ = hangchild3($1, $3, nil, $6); }
+| Tfor '(' word Tin words ')' nl cmd       { $$ = hangchild3($1, $3, $5, $8); }
+| Twhile paren nl cmd                      { $$ = hangchild2($1, $2, 0, $4, 1); }
+| Tif paren nl ifbody                      { $$ = hangchild1($2, $1, 0); }
+| Tswitch '(' word ')' nl '{' casebody '}' { $$ = hangchild2($1, $3, 0, $7, 1); }
+
+basic:
+  executable
+| basic word    { $$ = maketree2(Targs, $1, $2); }
+| basic redir   { $$ = maketree2(Targs, $1, $2); }
+
+atom:
+  nonkeyword
+| keyword             { $$ = maketree1(Tword, $1); }
+
+word:
+  atom
+| word '^' atom       { $$ = maketree2('^', $1, $3); }
+
+executable:
+  nonkeyword
+| executable '^' atom { $$ = maketree2('^', $1, $3); }
+
+nonkeyword:
+  Tword
+| '$' atom                  { $$ = maketree1('$', $2); }
+| '$' atom Tindex words ')' { $$ = maketree2(Tindex, $2, $4); }
+| '(' wordsnl ')'           { $$ = $2; }
+| Tcount atom               { $$ = maketree1(Tcount, $2); }
+| Tjoin atom                { $$ = maketree1(Tjoin, $2); }
+| '`'  block                { $$ = maketree1('`', $2); }
+//| Tredir block    { $$ = hangchild1($1, $2, 0); $$->type = Tpipefd; }
+
+keyword:
+    Tfor|Tin|Twhile|Tif|Telse|Tswitch|Tcase|Tbang|Tsubshell|Tfunc
+
+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'
+
+%%