From 02103dfd518faf327f7edc13695435308ddcead8 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Tue, 19 May 2020 14:02:28 -0700
Subject: feat: added prototype of stringizer & tokenizer macro operators

---
 sys/cmd/cc/pp.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 82 insertions(+), 10 deletions(-)

(limited to 'sys/cmd/cc/pp.c')

diff --git a/sys/cmd/cc/pp.c b/sys/cmd/cc/pp.c
index 8de4792..16fac29 100644
--- a/sys/cmd/cc/pp.c
+++ b/sys/cmd/cc/pp.c
@@ -110,8 +110,10 @@ opand(Lexer *lx)
         switch (tok.kind & ~Vmask) {
         case Vint: case Vlong: case Vvlong:
             return tok.val.i;
-        case Vint | Vun: case Vlong | Vun: case Vvlong | Vun:
+        case Vun|Vint : case Vun|Vlong : case Vun|Vvlong:
             return tok.val.ui;
+        case Vrune:
+            return tok.val.r;
         case Vchar:
             return tok.val.c;
         default:
@@ -383,7 +385,7 @@ enum
 {
     PPbeg  = 0x02,
     PParg  = 0x03,
-    PPtok  = 0x04,
+    PPcat  = 0x04,
     PPstr  = 0x05,
     PPvar  = 0x80,
 
@@ -435,9 +437,9 @@ static
 error
 ppdef(Lexer *lx)
 {
-    byte   b;
+    int    b;
     Sym   *sym;
-    int    i, n, dot;
+    int    i, j, f, n, dot;
     string s, a, buf, args[PPnarg];
 
     s = ident(lx);
@@ -503,12 +505,47 @@ ppdef(Lexer *lx)
 
             for (i = 0; i < n; i++) {
                 if (strcmp(lx->buf, args[i]) == 0) {
-                    goto Arg;
+                    goto Args;
                 }
             }
             str·appendlen(&buf, (lx->b - lx->buf), lx->buf);
             continue;
+        Args:
+            /* Check for argx ## argy OR argx##argy */
+            if (isspace(b)) {
+                b = getnsbyte(lx);
+                f = 1;
+            }
+            if (b == '#') {
+                b = getbyte(lx);
+                if (b != '#') {
+                    ungetbyte(lx);
+                    goto Arg;
+                }
+                b     = getnsbyte(lx);
+                lx->b = lx->buf;
+                while (isalnum(b) || b == '_') {
+                    *lx->b++ = b;
+                    b = getbyte(lx);
+                }
+                *lx->b = '\0';
+
+                for (j = 0; j < n; j++) {
+                    if (strcmp(lx->buf, args[j]) == 0)
+                        goto CatArgs;
+                }
+                errorat(lx->pos, "macro operator '##' must be terminated by valid variable identifier");
+                goto Bad;
+        CatArgs:
+                str·appendbyte(&buf, PPcat);
+                str·appendbyte(&buf, 'a' + i);
+                str·appendbyte(&buf, 'a' + j);
+                continue;
+            }
         Arg:
+            if (f)
+                ungetbyte(lx);
+
             str·appendbyte(&buf, PParg);
             str·appendbyte(&buf, 'a' + i);
             continue;
@@ -564,8 +601,29 @@ ppdef(Lexer *lx)
             break;
         }
 
-        if (b == '#' && n > 0) {
-            panicf("tokenizer needs implementation");
+        if (b == '#') {
+            b = getnsbyte(lx);
+            if (b == '#') {
+                errorat(lx->pos, "macro operator '##' must be proceeded by a valid variable identifier");
+                goto Bad;
+            }
+            lx->b = lx->buf;
+            while (isalnum(b) || b == '_') {
+                *lx->b++ = b;
+                b = getbyte(lx);
+            }
+            *lx->b = '\0';
+
+            for (i = 0; i < n; i++) {
+                if (strcmp(lx->buf, args[i]) == 0)
+                    goto Str;
+            }
+            errorat(lx->pos, "macro operator '#' must be followed by a valid variable identifier");
+            goto Bad;
+        Str:
+            str·appendbyte(&buf, PPstr);
+            str·appendbyte(&buf, 'a' + i);
+            continue;
         }
 
         str·appendbyte(&buf, b);
@@ -578,10 +636,12 @@ ppdef(Lexer *lx)
     if (dot) 
         *buf |= PPvar;
 
-    sym = defmacro(lx, s, buf);
+    lx->b = lx->buf;
+    sym   = defmacro(lx, s, buf);
     return 0;
 Bad:
     errorat(lx->pos, "failed parse of #define macro '%s'", s);
+    lx->b = lx->buf;
     ppend(lx);
     return 1;
 }
@@ -733,9 +793,21 @@ expandmacro(Lexer *lx, Sym *s, byte *dst)
             dst += strlen(arg[b]);
             break;
 
-        case PPtok:
         case PPstr:
-            panicf("haven't implemented");
+            b = *it++;
+            b -= 'a';
+            *dst++ = '"';
+            strcpy(dst, arg[b]);
+            *dst++ = '"';
+            break;
+
+        case PPcat:
+            b = *it++;
+            b -= 'a';
+            strcpy(dst, arg[b]);
+            b = *it++;
+            b -= 'a';
+            strcpy(dst, arg[b]);
             break;
 
         case '\0':
-- 
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