Feat: word operators and more robust crashing

Added the length and concatenate operators.
Slightly improved the robustness on syntax errors.

1 files changed, 24 insertions, 11 deletions

diff --git a/sys/cmd/rc/syntax.y b/sys/cmd/rc/syntax.y
index a580cb0..469260f 100644
--- a/sys/cmd/rc/syntax.y
+++ b/sys/cmd/rc/syntax.y
@@ -1,5 +1,5 @@
-%token Tword Tif Telse Tbang
-%token Targs
+%token Tword Twords Tif Telse Tbang
+%token Targs Tindex
 %token Tbasic Tparen Tblock
 
 %define parse.error verbose
@@ -12,18 +12,18 @@
 %}
 
 /* operator precendence: lowest first */
-%right Telse
-%left  Twhile
+%left  Twhile Telse
 %left  '\n'
 %left  Tbang
-%right '$'
+%right '$' 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 atom arg args;
+%type<tree> cmd basic executable nonkeyword keyword word words wordsnl atom arg args;
 %type<tree> Tbang;
 %type<tree> Tword Tif Telse;
 
@@ -74,21 +74,21 @@ cmd:
 
 basic:
   executable
-| basic word { $$ = maketree2(Targs, $1, $2); }
+| basic word          { $$ = maketree2(Targs, $1, $2); }
 
 arg: word
 
 args:
   arg
-| args arg { $$ = maketree2(Targs, $1, $2); }
+| args arg            { $$ = maketree2(Targs, $1, $2); }
 
 atom:
   nonkeyword
-| keyword     { $$ = maketree1(Tword, $1); }
+| keyword             { $$ = maketree1(Tword, $1); }
 
 word:
   atom
-| word '^' atom { $$ = maketree2('^', $1, $3); }
+| word '^' atom       { $$ = maketree2('^', $1, $3); }
 
 executable:
   nonkeyword
@@ -96,11 +96,24 @@ executable:
 
 nonkeyword:
   Tword
-| '$' atom { $$ = maketree1('$', $2); }
+| '$' atom        { $$ = maketree1('$', $2); }
+| '(' wordsnl ')' { $$ = $2; }
+| Tcount atom     { $$ = maketree1(Tcount, $2); }
+| Tflat atom      { $$ = maketree1(Tflat, $2); }
+//| '`'  block      { $$ = maketree1('`', $2); }
 
 keyword:
     Tif|Telse
 
+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'