Simplify `parse_binary_expr`

src/parser.cpp

@@ -3013,66 +3013,127 @@ i32 token_precedence(AstFile *f, TokenKind t) {
 	return 0;
 }
 
+// Ast *parse_binary_expr(AstFile *f, bool lhs, i32 prec_in) {
+// 	Ast *expr = parse_unary_expr(f, lhs);
+// 	for (i32 prec = token_precedence(f, f->curr_token.kind); prec >= prec_in; prec--) {
+// 		for (;;) {
+// 			Token op = f->curr_token;
+// 			i32 op_prec = token_precedence(f, op.kind);
+// 			if (op_prec != prec) {
+// 				// NOTE(bill): This will also catch operators that are not valid "binary" operators
+// 				break;
+// 			}
+// 			Token prev = f->prev_token;
+// 			switch (op.kind) {
+// 			case Token_if:
+// 			case Token_when:
+// 				if (prev.pos.line < op.pos.line) {
+// 					// NOTE(bill): Check to see if the `if` or `when` is on the same line of the `lhs` condition
+// 					goto loop_end;
+// 				}
+// 				break;
+// 			}
+// 			expect_operator(f); // NOTE(bill): error checks too
+
+// 			if (op.kind == Token_Question) {
+// 				Ast *cond = expr;
+// 				// Token_Question
+// 				Ast *x = parse_expr(f, lhs);
+// 				Token token_c = expect_token(f, Token_Colon);
+// 				Ast *y = parse_expr(f, lhs);
+// 				expr = ast_ternary_if_expr(f, x, cond, y);
+// 			} else if (op.kind == Token_if || op.kind == Token_when) {
+// 				Ast *x = expr;
+// 				Ast *cond = parse_expr(f, lhs);
+// 				Token tok_else = expect_token(f, Token_else);
+// 				Ast *y = parse_expr(f, lhs);
+
+// 				switch (op.kind) {
+// 				case Token_if:
+// 					expr = ast_ternary_if_expr(f, x, cond, y);
+// 					break;
+// 				case Token_when:
+// 					expr = ast_ternary_when_expr(f, x, cond, y);
+// 					break;
+// 				}
+// 			} else {
+// 				Ast *right = parse_binary_expr(f, false, prec+1);
+// 				if (right == nullptr) {
+// 					syntax_error(op, "Expected expression on the right-hand side of the binary operator '%.*s'", LIT(op.string));
+// 				}
+// 				if (op.kind == Token_or_else) {
+// 					// NOTE(bill): easier to handle its logic different with its own AST kind
+// 					expr = ast_or_else_expr(f, expr, op, right);
+// 				} else {
+// 					expr = ast_binary_expr(f, op, expr, right);
+// 				}
+// 			}
+
+// 			lhs = false;
+// 		}
+// 		loop_end:;
+// 	}
+// 	return expr;
+// }
+
 Ast *parse_binary_expr(AstFile *f, bool lhs, i32 prec_in) {
 	Ast *expr = parse_unary_expr(f, lhs);
-	for (i32 prec = token_precedence(f, f->curr_token.kind); prec >= prec_in; prec--) {
-		for (;;) {
-			Token op = f->curr_token;
-			i32 op_prec = token_precedence(f, op.kind);
-			if (op_prec != prec) {
-				// NOTE(bill): This will also catch operators that are not valid "binary" operators
-				break;
+	for (;;) {
+		Token op = f->curr_token;
+		i32 op_prec = token_precedence(f, op.kind);
+		if (op_prec < prec_in) {
+			// NOTE(bill): This will also catch operators that are not valid "binary" operators
+			break;
+		}
+		Token prev = f->prev_token;
+		switch (op.kind) {
+		case Token_if:
+		case Token_when:
+			if (prev.pos.line < op.pos.line) {
+				// NOTE(bill): Check to see if the `if` or `when` is on the same line of the `lhs` condition
+				goto loop_end;
 			}
-			Token prev = f->prev_token;
+			break;
+		}
+		expect_operator(f); // NOTE(bill): error checks too
+
+		if (op.kind == Token_Question) {
+			Ast *cond = expr;
+			// Token_Question
+			Ast *x = parse_expr(f, lhs);
+			Token token_c = expect_token(f, Token_Colon);
+			Ast *y = parse_expr(f, lhs);
+			expr = ast_ternary_if_expr(f, x, cond, y);
+		} else if (op.kind == Token_if || op.kind == Token_when) {
+			Ast *x = expr;
+			Ast *cond = parse_expr(f, lhs);
+			Token tok_else = expect_token(f, Token_else);
+			Ast *y = parse_expr(f, lhs);
+
 			switch (op.kind) {
 			case Token_if:
+				expr = ast_ternary_if_expr(f, x, cond, y);
+				break;
 			case Token_when:
-				if (prev.pos.line < op.pos.line) {
-					// NOTE(bill): Check to see if the `if` or `when` is on the same line of the `lhs` condition
-					goto loop_end;
-				}
+				expr = ast_ternary_when_expr(f, x, cond, y);
 				break;
 			}
-			expect_operator(f); // NOTE(bill): error checks too
-
-			if (op.kind == Token_Question) {
-				Ast *cond = expr;
-				// Token_Question
-				Ast *x = parse_expr(f, lhs);
-				Token token_c = expect_token(f, Token_Colon);
-				Ast *y = parse_expr(f, lhs);
-				expr = ast_ternary_if_expr(f, x, cond, y);
-			} else if (op.kind == Token_if || op.kind == Token_when) {
-				Ast *x = expr;
-				Ast *cond = parse_expr(f, lhs);
-				Token tok_else = expect_token(f, Token_else);
-				Ast *y = parse_expr(f, lhs);
-				
-				switch (op.kind) {
-				case Token_if:
-					expr = ast_ternary_if_expr(f, x, cond, y);
-					break;
-				case Token_when:
-					expr = ast_ternary_when_expr(f, x, cond, y);
-					break;
-				}
+		} else {
+			Ast *right = parse_binary_expr(f, false, op_prec+1);
+			if (right == nullptr) {
+				syntax_error(op, "Expected expression on the right-hand side of the binary operator '%.*s'", LIT(op.string));
+			}
+			if (op.kind == Token_or_else) {
+				// NOTE(bill): easier to handle its logic different with its own AST kind
+				expr = ast_or_else_expr(f, expr, op, right);
 			} else {
-				Ast *right = parse_binary_expr(f, false, prec+1);
-				if (right == nullptr) {
-					syntax_error(op, "Expected expression on the right-hand side of the binary operator '%.*s'", LIT(op.string));
-				}
-				if (op.kind == Token_or_else) {
-					// NOTE(bill): easier to handle its logic different with its own AST kind
-					expr = ast_or_else_expr(f, expr, op, right);	
-				} else {
-					expr = ast_binary_expr(f, op, expr, right);
-				}
+				expr = ast_binary_expr(f, op, expr, right);
 			}
-
-			lhs = false;
 		}
-		loop_end:;
+
+		lhs = false;
 	}
+	loop_end:;
 	return expr;
 }