ref: ed8f996d60efdfd7706c9e40a136a18f8422371d
parent: 1f09b3f3edd53ace12c72126f5bbad44f4ae8e8b
author: Roberto E. Vargas Caballero <k0ga@shike2.com>
date: Wed Sep 10 14:25:20 EDT 2014
Use different functions for every type of declarations This change helps to clarify the code because the number of if and branches decreases.
--- a/cc2/parser.c
+++ b/cc2/parser.c
@@ -15,6 +15,9 @@
#define NR_NODEPOOL 128
#define NR_EXPRESSIONS 64
+#define LOCAL 0
+#define GLOBAL 1
+
static Symbol *curfun;
static Node *stack[NR_STACKSIZ], **stackp = stack;
static Node *listexp[NR_EXPRESSIONS], **listp = listexp;
@@ -339,66 +342,6 @@
}
static void
-declaration(char *token)
-{- char class = token[0], *type, *name, *brace;
- Symbol *sym;
-
- switch (class) {- case 'P':
- if (!curfun)
- error(ESYNTAX);
- sym = local(token);
- sym->next = curfun->u.f.pars;
- curfun->u.f.pars = sym;
- break;
- case 'T':
- if (!curfun)
- error(ESYNTAX);
- sym = local(token);
- break;
- case 'R': case 'A':
- if (!curfun)
- error(ESYNTAX);
- sym = local(token);
- sym->next = curfun->u.f.vars;
- curfun->u.f.vars = sym;
- break;
- case 'X':
- sym = global(token);
- sym->extrn = 1;
- break;
- case 'Y':
- sym = global(token);
- break;
- case 'G':
- sym = global(token);
- sym->public = 1;
- break;
- }
-
- type = strtok(NULL, "\t");
- if (type[0] == 'F') {- sym->type = FUN;
- } else {- sym->type = VAR;
- sym->u.v.sclass = class;
- sym->u.v.type = gettype(type);
- }
- if (name = strtok(NULL, "\t"))
- sym->name = xstrdup(name);
- if (brace = strtok(NULL, "\t")) {- if (brace[0] != '{' || type[0] != 'F' || curfun)- error(ESYNTAX);
- sym->u.f.vars = NULL;
- sym->u.f.pars = NULL;
- curfun = sym;
- listp = listexp;
- newp = nodepool;
- }
-}
-
-static void
deflabel(char *token)
{Symbol *sym;
@@ -420,6 +363,76 @@
curfun = NULL;
}
+static Symbol *
+declaration(uint8_t t, char *token)
+{+ static Symbol *(*tbl[2])(char *)= {+ [LOCAL] = local, [GLOBAL] = global
+ };
+ Symbol *sym = (*tbl[t])(token);
+ char *s;
+
+ if (t == LOCAL && !curfun)
+ error(ESYNTAX);
+ if (sym->name)
+ free(sym->name);
+ memset(sym, 0, sizeof(*sym));
+ sym->type = VAR;
+ sym->u.v.sclass = token[0];
+
+ if ((s = strtok(NULL, "\t")) == NULL)
+ error(ESYNTAX);
+ sym->u.v.type = gettype(s);
+ if ((s = strtok(NULL, "\t")) != NULL)
+ sym->name = xstrdup(s);
+
+ return sym;
+}
+
+static void
+globdcl(char *token)
+{+ Symbol *sym = declaration(GLOBAL, token);
+
+ switch (token[0]) {+ case 'X':
+ sym->extrn = 1;
+ break;
+ case 'G':
+ sym->public = 1;
+ break;
+ }
+
+ if (sym->u.v.type != NULL)
+ return;
+
+ if (curfun)
+ error(ESYNTAX);
+
+ sym->type = FUN;
+ sym->u.f.vars = NULL;
+ sym->u.f.pars = NULL;
+ curfun = sym;
+ listp = listexp;
+ newp = nodepool;
+}
+
+static void
+paramdcl(char *token)
+{+ Symbol *sym = declaration(LOCAL, token);
+ sym->next = curfun->u.f.pars;
+ curfun->u.f.pars = sym;
+}
+
+static void
+localdcl(char *token)
+{+ Symbol *sym = declaration(LOCAL, token);
+ sym->next = curfun->u.f.vars;
+ curfun->u.f.vars = sym;
+}
+
void
parse(void)
{@@ -439,8 +452,14 @@
case 'S':
/* struct */
break;
- case 'Y': case 'T': case 'G': case 'A': case 'R': case 'P':
- fun = declaration;
+ case 'P':
+ fun = paramdcl;
+ break;
+ case 'A': case 'R': case 'T':
+ fun = localdcl;
+ break;
+ case 'Y': case 'G':
+ fun = globdcl;
break;
case '}':
fun = endfunction;
--
⑨