whatever

1 files changed, 135 insertions, 14 deletions

diff --git a/src/main.c b/src/main.c
index a38a66a..bc40806 100644
--- a/src/main.c
+++ b/src/main.c
@@ -80,10 +80,13 @@ new_token(TokenType type, char *start, char *end)
 	return tok;
 }
 
-static bool
-is_punct(int c)
+static int
+is_punct(const char *p)
 {
-	return (strchr("+-/*();", c) != NULL);
+	if (strchr("=!<>", p[0]) != NULL && p[1] == '=')
+		return 2;
+
+	return (strchr("+-/*()<>;", p[0]) != NULL);
 }
 
 static Token *
@@ -106,9 +109,10 @@ tokenize(char *p)
 			continue;
 		}
 
-		if (is_punct(*p)) {
-			cur = cur->next = new_token(TOK_PUNCT, p, p + 1);
-			p += 1;
+		const int punct = is_punct(p);
+		if (punct) {
+			cur = cur->next = new_token(TOK_PUNCT, p, p + punct);
+			p += punct;
 			continue;
 		}
 
@@ -128,11 +132,16 @@ tokenize(char *p)
 }
 
 typedef enum {
-	NOD_ADD,
-	NOD_SUB,
-	NOD_MUL,
-	NOD_DIV,
-	NOD_NUM,
+	NOD_ADD, // +
+	NOD_SUB, // -
+	NOD_MUL, // *
+	NOD_DIV, // /
+	NOD_EQU, // ==
+	NOD_NEQ, // !=
+	NOD_LT,  // <
+	NOD_LE,  // <=
+	NOD_NUM, // integer
+	NOD_EXPR_STMT,
 } NodeType;
 
 typedef struct Node Node;
@@ -140,6 +149,7 @@ struct Node {
 	NodeType type;
 	Node *lhs;
 	Node *rhs;
+	Node *next;
 	int val;
 };
 
@@ -163,6 +173,12 @@ new_binary(NodeType type, Node *lhs, Node *rhs)
 }
 
 static Node *
+new_unary(NodeType type, Node *node)
+{
+	return new_binary(type, node, NULL);
+}
+
+static Node *
 new_num(int val)
 {
 	Node *const node = new_node(NOD_NUM);
@@ -171,12 +187,74 @@ new_num(int val)
 }
 
 static Node *expr(Token **rest, Token *tok);
+static Node *expr_stmt(Token **rest, Token *tok);
+static Node *equality(Token **rest, Token *tok);
+static Node *relational(Token **rest, Token *tok);
+static Node *add(Token **rest, Token *tok);
 static Node *mul(Token **rest, Token *tok);
 static Node *primary(Token **rest, Token *tok);
 
-// expr = mul ("+" mul | "-" mul)*
+static Node
+*expr(Token **rest, Token *tok)
+{
+	return equality(rest, tok);
+}
+
+static Node
+*equality(Token **rest, Token *tok)
+{
+	Node *node = relational(&tok, tok);
+
+for (;;) {
+		if (equal(tok, "==")) {
+			node = new_binary(NOD_EQU, node, relational(&tok, tok->next));
+			continue;
+		}
+
+		if (equal(tok, "!=")) {
+			node = new_binary(NOD_NEQ, node, relational(&tok, tok->next));
+			continue;
+		}
+
+		*rest = tok;
+		return node;
+	}
+}
+
+static Node
+*relational(Token **rest, Token *tok)
+{
+	Node *node = add(&tok, tok);
+
+	for (;;) {
+		if (equal(tok, "<")) {
+			node = new_binary(NOD_LT, node, add(&tok, tok->next));
+			continue;
+		}
+
+		if (equal(tok, "<=")) {
+			node = new_binary(NOD_LE, node, add(&tok, tok->next));
+			continue;
+		}
+
+		if (equal(tok, ">")) {
+			node = new_binary(NOD_LT, add(&tok, tok->next), node);
+			continue;
+		}
+
+		if (equal(tok, ">=")) {
+			node = new_binary(NOD_LE, add(&tok, tok->next), node);
+			continue;
+		}
+
+		*rest = tok;
+		return node;
+	}
+}
+
+// add = mul ("+" mul | "-" mul)*
 static Node *
-expr(Token **rest, Token *tok)
+add(Token **rest, Token *tok)
 {
 	Node *node = mul(&tok, tok);
 
@@ -237,6 +315,20 @@ primary(Token **rest, Token *tok)
 	return NULL;
 }
 
+static Node *
+stmt(Token **rest, Token *tok)
+{
+	return expr_stmt(rest, tok);
+}
+
+static Node
+*expr_stmt(Token **rest, Token *tok)
+{
+	Node *const node = new_unary(NOD_EXPR_STMT, expr(&tok, tok));
+	*rest = skip(tok, ";");
+	return node;
+}
+
 // code generator
 
 static int depth;
@@ -267,6 +359,18 @@ gen_expr(Node *node)
 	case NOD_DIV:
 		printf("\tDIV\n");
 		return;
+	case NOD_EQU:
+		printf("\tEQU\n");
+		return;
+	case NOD_NEQ:
+		printf("\tNEQ\n");
+		return;
+	case NOD_LT:
+		printf("\tLTH\n");
+		return;
+	case NOD_LE:
+		printf("\tGTH NOT\n");
+		return;
 	default:
 		break;
 	}
@@ -274,6 +378,23 @@ gen_expr(Node *node)
 	error("invalid expression %d", node->type);
 }
 
+static void
+codegen(Node *node)
+{
+	gen_expr(node);
+}
+
+// program = stmt*
+static Node *
+parse(Token *tok)
+{
+	Node head = {0};
+	Node *cur = &head;
+	while (tok->type != TOK_EOF)
+		cur = cur->next = stmt(&tok, tok);
+	return head.next;
+}
+
 int
 main(int argc, char **argv)
 {
@@ -288,7 +409,7 @@ main(int argc, char **argv)
 		error("extra token");
 
 	printf("main:\n");
-	gen_expr(node);
+	codegen(node);
 	printf("\tRET\n");
 
 	assert(depth == 1);