release: rc-1.4

1 files changed, 226 insertions, 0 deletions

diff --git a/var.c b/var.c
new file mode 100644
index 0000000..ef780b3
--- /dev/null
+++ b/var.c
@@ -0,0 +1,226 @@
+/* var.c: provide "public" functions for adding and removing variables from the symbol table */
+
+#include "rc.h"
+
+static void colonassign(char *, List *, bool);
+static void listassign(char *, List *, bool);
+static int hasalias(char *);
+
+static char *const aliases[] = {
+	"home", "HOME", "path", "PATH", "cdpath", "CDPATH"
+};
+
+/* assign a variable in List form to a name, stacking if appropriate */
+
+extern void varassign(char *name, List *def, bool stack) {
+	Variable *new;
+	List *newdef = listcpy(def, ealloc); /* important to do the listcpy first; get_var_place() frees old values */
+	new = get_var_place(name, stack);
+	new->def = newdef;
+	new->extdef = NULL;
+#ifdef READLINE /* need to reset readline() every time TERM or TERMCAP changes */
+	if (interactive && (streq(name, "TERM") || streq(name, "TERMCAP"))) {
+		extern void rl_reset_terminal(char *);
+		rl_reset_terminal(NULL);
+	}
+#endif
+}
+
+/* assign a variable in string form. Check to see if it is aliased (e.g., PATH and path) */
+
+extern bool varassign_string(char *extdef) {
+	static bool aliasset[arraysize(aliases)] = {
+		FALSE, FALSE, FALSE, FALSE, FALSE, FALSE
+	};
+	char *name = get_name(extdef);
+	Variable *new;
+	int i;
+	if (name == NULL)
+		return FALSE; /* add it to bozo env */
+	if ((i = hasalias(name)) != -1) {
+		aliasset[i] = TRUE;
+		i ^= 1;			 	/* set i to the "opposite" case subscript and */
+		if (i&1 && aliasset[i])		/* don't alias variables that are already set in upper case */
+			return TRUE;
+	}
+	new = get_var_place(name, FALSE);
+	new->def = NULL;
+	new->extdef = ealloc(strlen(extdef) + 1);
+	strcpy(new->extdef, extdef);
+	if (i != -1)
+		alias(name, varlookup(name), FALSE);
+	return TRUE;
+}
+
+/*
+   Return a List based on a name lookup. If the list is in external (string) form,
+   convert it to internal (List) form. Treat $n (n is an integer) specially as $*(n).
+   Also check to see if $status is being dereferenced. (we lazily evaluate the List
+   associated with $status)
+*/
+
+extern List *varlookup(char *name) {
+	Variable *look;
+	List *ret, *l;
+	int sub;
+	if (streq(name, "status"))
+		return sgetstatus();
+	if (streq(name, "apids"))
+		return sgetapids();
+	if (*name != '\0' && (sub = a2u(name)) != -1) { /* handle $1, $2, etc. */
+		for (l = varlookup("*"); l != NULL && sub != 0; --sub)
+			l = l->n;
+		if (l == NULL)
+			return NULL;
+		ret = nnew(List);
+		ret->w = l->w;
+		ret->m = NULL;
+		ret->n = NULL;
+		return ret;
+	}
+	look = lookup_var(name);
+	if (look == NULL)
+		return NULL; /* not found */
+	if (look->def != NULL)
+		return look->def;
+	if (look->extdef == NULL)
+		return NULL; /* variable was set to null, e.g., a=() echo foo */
+	ret = parse_var(name, look->extdef);
+	if (ret == NULL) {
+		look->extdef = NULL;
+		return NULL;
+	}
+	return look->def = ret;
+}
+
+/* lookup a variable in external (string) form, converting if necessary. Used by makeenv() */
+
+extern char *varlookup_string(char *name) {
+	Variable *look;
+	look = lookup_var(name);
+	if (look == NULL)
+		return NULL;
+	if (look->extdef != NULL)
+		return look->extdef;
+	if (look->def == NULL)
+		return NULL;
+	return look->extdef = list2str(name, look->def);
+}
+
+/* remove a variable from the symtab. "stack" determines whether a level of scoping is popped or not */
+
+extern void varrm(char *name, bool stack) {
+	int i = hasalias(name);
+	if (streq(name, "*") && !stack) { /* when assigning () to $*, we want to preserve $0 */
+		varassign("*", varlookup("0"), FALSE);
+		return;
+	}
+	delete_var(name, stack);
+	if (i != -1)
+		delete_var(aliases[i^1], stack);
+}
+
+/* assign a value (List) to a variable, using array "a" as input. Used to assign $* */
+
+extern void starassign(char *dollarzero, char **a, bool stack) {
+	List *s, *var;
+	var = nnew(List);
+	var->w = dollarzero;
+	if (*a == NULL) {
+		var->n = NULL;
+		varassign("*", var, stack);
+		return;
+	}
+	var->n = s = nnew(List);
+	while (1) {
+		s->w = *a++;
+		if (*a == NULL) {
+			s->n = NULL;
+			break;
+		} else
+			s = s->n = nnew(List);
+	}
+	varassign("*", var, stack);
+}
+
+/* (ugly name, huh?) assign a colon-separated value to a variable (e.g., PATH) from a List (e.g., path) */
+
+static void colonassign(char *name, List *def, bool stack) {
+	List dud;
+	if (def == NULL) {
+		varassign(name, NULL, stack);
+		return;
+	}
+	dud.w = nprint("%-L", def, ":");
+	dud.n = NULL;
+	varassign(name, &dud, stack);
+}
+
+/* assign a List variable (e.g., path) from a colon-separated string (e.g., PATH) */
+
+static void listassign(char *name, List *def, bool stack) {
+	List *val, *r;
+	char *v, *w;
+	if (def == NULL) {
+		varassign(name, NULL, stack);
+		return;
+	}
+	v = def->w;
+	r = val = enew(List);
+	while ((w = strchr(v, ':')) != NULL) {
+		*w = '\0';
+		r->w = ecpy(v);
+		*w = ':';
+		v = w + 1;
+		r->n = enew(List);
+		r = r->n;
+	}
+	r->w = ecpy(v);
+	r->n = NULL;
+	varassign(name, val, stack);
+}
+
+/* check to see if a particular variable is aliased; return -1 on failure, or the index */
+
+static int hasalias(char *name) {
+	int i;
+	for (i = 0; i < arraysize(aliases); i++)
+		if (streq(name, aliases[i]))
+			return i;
+	return -1;
+}
+
+/* alias a variable to its lowercase equivalent. function pointers are used to specify the conversion function */
+
+extern void alias(char *name, List *s, bool stack) {
+	static void (*vectors[])(char *, List *, bool) = {
+		varassign, varassign, colonassign, listassign, colonassign, listassign
+	};
+	int i = hasalias(name);
+	if (i != -1)
+		(*vectors[i])(aliases[i^1], s, stack); /* xor hack to reverse case of alias entry */
+}
+
+extern void prettyprint_var(int fd, char *name, List *s) {
+	int i;
+	static const char * const keywords[] = {
+		"if", "in", "fn", "for", "else", "switch", "while", "case"
+	};
+	if (s == NULL) {
+		fprint(fd, "%S=()\n", name);
+		return;
+	}
+	if (streq(name, "*")) {
+		s = s->n;
+		if (s == NULL)
+			return; /* Don't print $0, and if $* is not set, skip it */
+	}
+	for (i = 0; i < arraysize(keywords); i++)
+		if (streq(keywords[i], name)) {
+			fprint(fd, "%#S=", name);
+			goto value;
+		}
+	fprint(fd, "%S=", name);
+value:
+	fprint(fd, s->n == NULL ? "%L\n" : "(%L)\n", s, " ");
+}