From bf03074e346b004659196b6c17eee04dbffd3ac2 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Fri, 15 Oct 2021 16:18:02 -0700
Subject: feat(rc): working prototype of input->compile->print loop

---
 sys/cmd/rc/var.c | 271 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 271 insertions(+)
 create mode 100644 sys/cmd/rc/var.c

(limited to 'sys/cmd/rc/var.c')

diff --git a/sys/cmd/rc/var.c b/sys/cmd/rc/var.c
new file mode 100644
index 0000000..f0e5f5b
--- /dev/null
+++ b/sys/cmd/rc/var.c
@@ -0,0 +1,271 @@
+#include "rc.h"
+
+static Var *globals[512];
+
+// -----------------------------------------------------------------------
+// internals
+
+static
+int
+hash(char *s, int len)
+{
+    int h =0, i = 1;
+    while(*s)
+        h += *s++*i++;
+
+    h %= len;
+    return h < 0 ? h+len : h;
+}
+
+static
+void
+·setvar(char *name, Word *val, int call)
+{
+    Var *v = var(name);
+    freeword(v->val);
+
+    v->val = val;
+    v->new = 1; // this never turns off?
+
+    if(call && v->update)
+        v->update(v);
+}
+
+static
+char*
+list2strcolon(Word *words)
+{
+    char *value, *s, *t;
+    int len = 0;
+    Word *ap;
+    for(ap = words;ap;ap = ap->link)
+        len+=1+strlen(ap->str);
+
+    value = emalloc(len+1);
+
+    s = value;
+    for(ap = words; ap; ap = ap->link){
+        for(t = ap->str;*t;) *s++=*t++;
+        *s++=':';
+    }
+
+    if(s==value)
+        *s='\0';
+    else 
+        s[-1]='\0';
+
+    return value;
+}
+
+static
+void
+littlepath(Var *v)
+{
+    /* convert $path to $PATH */
+    char *p;
+    Word *w;
+
+    p = list2strcolon(v->val);
+    w = emalloc(sizeof(*w));
+    w->str  = p;
+    w->link = nil;
+
+    ·setvar("PATH", w, 1);
+}
+
+static
+void
+bigpath(Var *v)
+{
+    /* convert $PATH to $path */
+    char *p, *q;
+    Word **l, *w;
+
+    if(v->val == nil){
+        ·setvar("path", nil, 0);
+        return;
+    }
+
+    p = v->val->str;
+    w = nil;
+    l = &w;
+
+    /* Doesn't handle escaped colon nonsense. */
+    if(p[0] == 0)
+        p = nil;
+
+    while(p){
+        q = strchr(p, ':');
+        if(q)
+            *q = 0;
+
+        *l = makeword(p[0] ? p : ".", nil);
+        l  = &(*l)->link;
+
+        if(q){
+            *q = ':';
+            p = q+1;
+        }else
+            p = nil;
+    }
+    ·setvar("path", w, 0);
+}
+
+
+
+// -----------------------------------------------------------------------
+// exports
+
+Var*
+makevar(char *name, Var *link)
+{
+    Var *v = emalloc(sizeof(*v));
+
+    v->name    = name;
+    v->val     = 0;
+    v->new     = 0;
+    v->newfunc = 0;
+    v->link    = link;
+    v->func    = nil;
+    v->update  = nil;
+
+    return v;
+}
+
+void
+setvar(char *name, Word *val)
+{
+    ·setvar(name, val, 1);
+}
+
+Var*
+definevar(char *name, Var *link)
+{
+    Var *v = emalloc(sizeof(*v));
+
+    v->name = name;
+    v->val  = 0;
+    v->link = link;
+
+    return v;
+}
+
+Var*
+globalvar(char *name)
+{
+    int  h;
+    Var *v;
+
+    h = hash(name, arrlen(globals));
+
+    if(strcmp(name,"PATH")==0){
+        flush(errio);
+    }
+
+    for(v = globals[h]; v; v = v->link){
+        if(strcmp(v->name, name) == 0){
+            return v;
+        }
+    }
+
+    return globals[h] = definevar(strdup(name), globals[h]);
+}
+
+Var*
+var(char *name)
+{
+    Var *v;
+    if(shell){
+        for(v = shell->local; v; v=v->link)
+            if(strcmp(v->name, name) == 0)
+                return v;
+    }
+    return globalvar(name);
+}
+
+static
+int
+cmpenv(const void *a, const void *b)
+{
+    return strcmp(*(char**)a, *(char**)b);
+}
+
+char**
+mkenv(void)
+{
+    char **env, **ep, *p, *q;
+    Var **h, *v;
+    Word *a;
+    int nvar=0, nchr=0, sep;
+
+#define BODY                                \
+        if((v==var(v->name)) && v->val){    \
+            nvar++;                         \
+            nchr+=strlen(v->name)+1;        \
+            for(a=v->val;a;a=a->link)       \
+                nchr+=strlen(a->str)+1;     \
+        }
+
+    for(v= shell->local; v; v=v->link){
+        BODY
+    }
+    for(h=globals; h!=arrend(globals); h++){
+        for(v = *h; v; v=v->link){
+            BODY
+        }
+    }
+
+#undef  BODY
+
+    env=emalloc((nvar+1)*sizeof(*env)+nchr);
+    ep=env;
+    p=(char *)&env[nvar+1];
+
+#define BODY                            \
+    if((v==var(v->name)) && v->val){    \
+        *ep++=p;                        \
+        q=v->name;                      \
+        while(*q)                       \
+            *p++=*q++;                  \
+        sep='=';                        \
+        for(a=v->val;a;a=a->link){      \
+            *p++=sep;                   \
+            sep='\1';                   \
+            q=a->str;                   \
+            while(*q)                   \
+                *p++=*q++;              \
+        }                               \
+        *p++='\0';                      \
+    }
+
+    for(v=shell->local; v; v=v->link){
+        BODY
+    }
+    for(h=globals; h!=arrend(globals); h++){
+        for(v = *h; v; v=v->link){
+            BODY
+        }
+    }
+#undef  BODY
+
+    *ep=0;
+
+    qsort((char *)env, nvar, sizeof ep[0], cmpenv);
+    return env;	
+}
+
+void
+initpath(void)
+{
+    Var *v;
+
+    v = globalvar("path");
+    v->update = littlepath;
+
+    v = globalvar("PATH");
+    v->update = bigpath;
+
+    flush(errio);
+    bigpath(v);
+}
+
-- 
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