feat(rc): keywords now recognized. for and while loop

Prototypes for loops sketched. This required recognizing keywords and
returning from yylex. Debugging/testing will be required.

9 files changed, 146 insertions, 9 deletions

diff --git a/sys/cmd/rc/code.c b/sys/cmd/rc/code.c
index 0723279..786f284 100644
--- a/sys/cmd/rc/code.c
+++ b/sys/cmd/rc/code.c
@@ -163,6 +163,43 @@ walk(Tree *node)
         }
         node = n;
         break;
+    /* control structures */
+    case Twhile:
+        addr1 = interpreter.i; // head of loop
+        walk(node->child[0]);
+        if(addr1 == interpreter.i)
+            fatal("TODO");
+        emitf(Xtrue);
+        addr2 = emiti(0); // goto end of loop
+
+        walk(node->child[1]);
+        emitf(Xgoto);
+        emiti(addr1);   // goto top of loop
+        storepc(addr2);
+        break;
+
+    case Tfor:
+        emitf(Xmark);
+        if(node->child[1]){ // for( x in X )
+            walk(node->child[1]);
+            // emitf(Xglob)
+        }else{              // for(X)
+            fatal("TODO");
+        }
+        emitf(Xmark); // null initial value for Xlocal
+        emitf(Xmark);
+        walk(node->child[0]);
+        emitf(Xlocal);
+
+        addr1 = emitf(Xfor);
+        addr2 = emiti(0);
+
+        walk(node->child[2]);
+        emitf(Xgoto);
+        emiti(addr1);
+        storepc(addr2);
+        emitf(Xunlocal);
+        break;
 
     /* forks */
     case '&':
diff --git a/sys/cmd/rc/exec.c b/sys/cmd/rc/exec.c
index fbcfb9b..5f3c6d6 100644
--- a/sys/cmd/rc/exec.c
+++ b/sys/cmd/rc/exec.c
@@ -656,6 +656,31 @@ Xfalse(void)
         runner->code.i = runner->code.exe[runner->code.i].i;
 }
 
+void
+Xgoto(void)
+{
+    runner->code.i = runner->code.exe[runner->code.i].i;
+}
+
+void
+Xfor(void)
+{
+    if(!runner->args->word){
+        poplist();
+        runner->code.i = runner->code.exe[runner->code.i].i;
+    }else{
+        freelist(runner->local->val);
+
+        runner->local->val = runner->args->word;
+        runner->local->new = 1;
+        runner->args->word = runner->args->word->link;
+
+        runner->local->val->link = nil;
+        runner->code.i++;
+    }
+
+}
+
 static
 Word*
 catlist(Word *l, Word *r, Word *tail)
diff --git a/sys/cmd/rc/exec.h b/sys/cmd/rc/exec.h
index 635eb1d..a3a6ae9 100644
--- a/sys/cmd/rc/exec.h
+++ b/sys/cmd/rc/exec.h
@@ -8,12 +8,14 @@
  */
 
 void Xmark(void);           // Xmark            marks stack location for word
-void Xtrue(void);           // Xtrue{...}       execute {} if true
-void Xfalse(void);          // Xfalse{...}      execute {} if false
-void Xdollar(void);         // Xdollar(name)    get value of name
 void Xindex(void);          // Xindex
 void Xlocal(void);          // Xlocal(name,val) create local variable, assign value
 void Xunlocal(void);        // Xunlocal         delete local variable
+void Xdollar(void);         // Xdollar(name)    get value of name
+void Xtrue(void);           // Xtrue{...}       execute {} if true
+void Xfalse(void);          // Xfalse{...}      execute {} if false
+void Xgoto(void);           // Xgoto[addr]      goto address
+void Xfor(void);            // Xfor(var, list){... Xreturn}
 void Xreadcmd(void);        //
 void Xassign(void);
 void Xbang(void);
diff --git a/sys/cmd/rc/lex.c b/sys/cmd/rc/lex.c
index 6065981..596021b 100644
--- a/sys/cmd/rc/lex.c
+++ b/sys/cmd/rc/lex.c
@@ -386,7 +386,10 @@ yylex(void)
         *w = 0;
 
     node = token(Tword, lexer.buf);
-    // TODO: keywords
+    if((c=iskeyword(lexer.buf))){
+        node->type = c;
+        lexer.hadword = 0;
+    }
 
     node->quoted = 0;
 
diff --git a/sys/cmd/rc/main.c b/sys/cmd/rc/main.c
index 9e35a87..12f0859 100644
--- a/sys/cmd/rc/main.c
+++ b/sys/cmd/rc/main.c
@@ -56,6 +56,7 @@ main(int argc, char *argv[])
 
     initenv();
     initpath();
+    initkeywords();
     initshell();
 
     // enablevi();
diff --git a/sys/cmd/rc/parse.c b/sys/cmd/rc/parse.c
index fa3e165..1b29d41 100644
--- a/sys/cmd/rc/parse.c
+++ b/sys/cmd/rc/parse.c
@@ -632,7 +632,7 @@ static const yytype_int8 yydefact[] =
       26,     0,     0,     0,     0,    26,    26,     0,    22,    50,
        0,     0,     0,    69,    26,     0,     0,     0,    24,    26,
       26,    26,     4,    27,    41,    48,     0,    26,    72,    72,
-       0,    34,    35,    58,    57,    59,    60,    61,    62,    63,
+       0,    34,    35,    57,    58,    59,    60,    61,    62,    63,
       64,    65,    66,    46,    23,    44,    45,    51,    54,    55,
        0,     0,    12,    26,     6,    56,     1,     3,    24,    28,
        5,    33,    32,    72,    72,    72,    10,    11,    43,    42,
diff --git a/sys/cmd/rc/rc.h b/sys/cmd/rc/rc.h
index 3090002..e35c3e4 100644
--- a/sys/cmd/rc/rc.h
+++ b/sys/cmd/rc/rc.h
@@ -239,7 +239,6 @@ void background(Thread *, int);
 int   count(Word *); 
 Word  *makeword(char *str, Word *link);
 void   freeword(Word *w);
-void   initpath(void);
 
 /* var.c */
 Var *var(char*);
@@ -247,6 +246,11 @@ Var *definevar(char*, Var *);
 Var *globalvar(char*);
 Var *makevar(char *name, Var *link);
 void setvar(char *, Word *);
+int  iskeyword(char *);
+
+void initpath(void);
+void initkeywords(void);
+
 char **mkenv(void);
 
 /* code.c */
diff --git a/sys/cmd/rc/syntax.y b/sys/cmd/rc/syntax.y
index 58bef16..0bdc776 100644
--- a/sys/cmd/rc/syntax.y
+++ b/sys/cmd/rc/syntax.y
@@ -129,7 +129,7 @@ nonkeyword:
 //| Tredir block    { $$ = hangchild1($1, $2, 0); $$->type = Tpipefd; }
 
 keyword:
-    Tin|Tfor|Twhile|Tif|Telse|Tswitch|Tcase|Tbang|Tsubshell|Tfunc
+    Tfor|Tin|Twhile|Tif|Telse|Tswitch|Tcase|Tbang|Tsubshell|Tfunc
 
 words:
 /* empty */  { $$ = nil; }
diff --git a/sys/cmd/rc/var.c b/sys/cmd/rc/var.c
index 5e1e90c..3e9635f 100644
--- a/sys/cmd/rc/var.c
+++ b/sys/cmd/rc/var.c
@@ -1,6 +1,19 @@
 #include "rc.h"
+#include "parse.h"
+
+// TODO: string interning
+
+// -----------------------------------------------------------------------
+// globals
+
+struct Keyword 
+{
+    char *name;
+    int   type;
+};
 
 static Var *globals[512];
+static struct Keyword keywords[100]; // sparse map means less hits
 
 // -----------------------------------------------------------------------
 // internals
@@ -111,8 +124,6 @@ bigpath(Var *v)
     ·setvar("path", w, 0);
 }
 
-
-
 // -----------------------------------------------------------------------
 // exports
 
@@ -269,3 +280,57 @@ initpath(void)
     bigpath(v);
 }
 
+#define KEYWORDS \
+    KEYWORD("for",    Tfor) \
+    KEYWORD("in",     Tin) \
+    KEYWORD("while",  Twhile) \
+    KEYWORD("if",     Tif) \
+    KEYWORD("else",   Telse) \
+    KEYWORD("switch", Tswitch) \
+    KEYWORD("case",   Tcase) \
+    KEYWORD("!",      Tbang) \
+    KEYWORD("@",      Tsubshell) \
+    KEYWORD("func",   Tfunc)
+
+void
+initkeywords(void)
+{
+    int i, s, j, h;
+#define KEYWORD(a, b) a,
+    static char *name[]  = { KEYWORDS };
+#undef KEYWORD
+#define KEYWORD(a, b) b,
+    static int type[] = { KEYWORDS };
+#undef KEYWORD
+
+    for(i = 0; i < arrlen(type); i++){
+        h = hash(name[i], arrlen(keywords));
+        for(s=0; s < arrlen(keywords); s++){
+            j = (h + s) % arrlen(keywords);
+            if(!keywords[j].type || strcmp(keywords[j].name, name[i]) == 0){
+                keywords[j].name = name[i];
+                keywords[j].type = type[i];
+                goto nextkeyword;
+            }
+        }
+    nextkeyword:;
+    }
+}
+
+int
+iskeyword(char *word)
+{
+    int i, s, h;
+
+    h = hash(word, arrlen(keywords));
+    for(s = 0; s < arrlen(keywords); s++){
+        i = (h + s) % arrlen(keywords);
+        if(!keywords[i].type)
+            return 0;
+        if(strcmp(keywords[i].name, word) == 0)
+            return keywords[i].type;
+    }
+    return 0;
+}
+
+#undef KEYWORDS