commit 84b452b

Add environments

  1@@ -8,16 +8,28 @@
  2 #define current_char(p, c) ((p)->src[(p)->pos] == (c))
  3 #define advance(p) ((p)->pos++)
  4 #define pos(p) ((p)->pos)
  5-#define peek(p) ((p)->pos + 1)
  6+#define peek(p) ((p)->src[(p)->pos + 1])
  7 
  8-typedef struct {
  9+typedef struct parser parser;
 10+typedef struct environment environment;
 11+
 12+struct parser {
 13 	const char* src;
 14 	size_t      pos;
 15 	expl_error  err;
 16-} parser;
 17+};
 18+
 19+struct environment {
 20+	char*      name;
 21+	expl_node* value;
 22+	environment*   next;
 23+};
 24 
 25+static int define(environment** env, const char* name, expl_node* value);
 26 static expl_node* expression(parser* p);
 27+static expl_node* evaluate(expl_node* n, environment** env);
 28 static expl_node* list(parser* p);
 29+static expl_node* lookup(environment* env, const char* name);
 30 static expl_node* value(parser* p, expl_type type);
 31 
 32 static void skipspace(parser* p);
 33@@ -26,6 +38,27 @@ static void unescape(char* src);
 34 
 35 static expl_node* newnode(expl_type type);
 36 static void freenode(expl_node* node);
 37+static void freeenv(environment* env);
 38+
 39+static int
 40+define(environment** env, const char* name, expl_node* value)
 41+{
 42+	environment* b = malloc(sizeof(*b));
 43+	if (!b)
 44+		return 0;
 45+
 46+	b->name = _strndup(name, strlen(name));
 47+	if (!b->name) {
 48+		free(b);
 49+		return 0;
 50+	}
 51+
 52+	b->value = value;
 53+	b->next = *env;
 54+	*env = b;
 55+
 56+	return 1;
 57+}
 58 
 59 static expl_node*
 60 expression(parser* p)
 61@@ -45,6 +78,15 @@ expression(parser* p)
 62 	}
 63 }
 64 
 65+static expl_node*
 66+evaluate(expl_node* n, environment** env)
 67+{
 68+	/* XXX */
 69+	(void) n;
 70+	(void) env;
 71+	return NULL;
 72+}
 73+
 74 static expl_node*
 75 list(parser* p)
 76 {
 77@@ -83,6 +125,18 @@ list(parser* p)
 78 	return node;
 79 }
 80 
 81+static expl_node*
 82+lookup(environment* env, const char* name)
 83+{
 84+	while (env) {
 85+		if (strcmp(env->name, name) == 0)
 86+			return env->value;
 87+		env = env->next;
 88+	}
 89+
 90+	return NULL;
 91+}
 92+
 93 static expl_node*
 94 value(parser* p, expl_type type)
 95 {
 96@@ -227,6 +281,17 @@ freenode(expl_node* node)
 97 	free(node);
 98 }
 99 
100+static void
101+freeenv(environment* env)
102+{
103+	while (env) {
104+		environment* next = env->next;
105+		free(env->name);
106+		free(env);
107+		env = next;
108+	}
109+}
110+
111 expl_node*
112 expl_parse(const char* source)
113 {
114@@ -285,7 +350,7 @@ expl_print(const expl_node* node, int depth)
115 int
116 main(void)
117 {
118-	expl_node* node = expl_parse("(fn (\"hi\n\n\n\" x) (* x x))");
119+	expl_node* node = expl_parse("(fn (\"hi\" x) (* x x))");
120 	expl_print(node, 0);
121 	freenode(node);
122 	return EXIT_SUCCESS;