add getln() function and calculator example

Runtime-allocated strings currently always leak memory, I will
definitely have to fix that.

examples/calculator.script

@@ -0,0 +1,22 @@
+put("Enter an operation (+, -, *, /): ")
+op := getln()
+if (!(op == "+" || op == "-" || op == "*" || op == "/")) {
+	put("Unknown operation: ")
+	putln(op)
+} else {
+	put("1st number: ")
+	n1 := float(getln())
+	put("2nd number: ")
+	n2 := float(getln())
+
+	put("Result: ")
+	if (op == "+") {
+		putln(n1 + n2)
+	} else if (op == "-") {
+		putln(n1 - n2)
+	} else if (op == "*") {
+		putln(n1 * n2)
+	} else if (op == "/") {
+		putln(n1 / n2)
+	}
+}

main.c

@@ -53,6 +53,18 @@ static Value fn_int(Value *args) {
 		case TypeVoid: break;
 		case TypeFloat: ret.Int = (ssize_t)args[0].Float; break;
 		case TypeInt:   ret.Int = args[0].Int;            break;
+		case TypeBool:  ret.Int = (ssize_t)args[0].Bool;  break;
+		case TypeArr:
+			if (args[0].Arr.is_string && args[0].Arr.type.kind == TypeChar) {
+				ssize_t endpos;
+				ret.Int = stoimax((char*)args[0].Arr.vals, args[0].Arr.len, 10, &endpos);
+				if (endpos != -1) {
+					set_err("Error converting from string to int");
+					return (Value){0};
+				}
+			} else
+				ASSERT_UNREACHED();
+			break;
 		default: ASSERT_UNREACHED();
 	}
 	return ret;
@@ -67,6 +79,18 @@ static Value fn_float(Value *args) {
 		case TypeVoid: break;
 		case TypeFloat: ret.Float = args[0].Float;        break;
 		case TypeInt:   ret.Float = (double)args[0].Int;  break;
+		case TypeBool:  ret.Float = (double)args[0].Bool; break;
+		case TypeArr:
+			if (args[0].Arr.is_string && args[0].Arr.type.kind == TypeChar) {
+				ssize_t endpos;
+				ret.Float = stod((char*)args[0].Arr.vals, args[0].Arr.len, &endpos);
+				if (endpos != -1) {
+					set_err("Error converting from string to float");
+					return (Value){0};
+				}
+			} else
+				ASSERT_UNREACHED();
+			break;
 		default: ASSERT_UNREACHED();
 	}
 	return ret;
@@ -92,6 +116,34 @@ static Value fn_sleep(Value *args) {
 	return (Value){0};
 }
 
+static Value fn_getln(Value *args) {
+	(void)args;
+
+	char *line = xmalloc(64);
+	size_t len = 0, cap = 64;
+	for (;;) {
+		int c = fgetc(stdin);
+		if (c == EOF)
+			break;
+		else if (c == '\n')
+			break;
+		if (len+1 > cap)
+			line = xrealloc(line, (cap *= 2));
+		line[len++] = c;
+	}
+
+	return (Value){
+		.type.kind = TypeArr,
+		.Arr = {
+			.is_string = true,
+			.type.kind = TypeChar,
+			.vals = line,
+			.len = len,
+			.cap = cap,
+		},
+	};
+}
+
 int main(int argc, const char **argv) {
 	/* parse arguments */
 	size_t nargs = argc - 1;
@@ -157,6 +209,7 @@ int main(int argc, const char **argv) {
 		{ .name = "float", .side_effects = false, .n_args = 1, .func = fn_float, },
 		{ .name = "pow",   .side_effects = false, .n_args = 2, .func = fn_pow,   },
 		{ .name = "sleep", .side_effects = true,  .n_args = 1, .func = fn_sleep, },
+		{ .name = "getln", .side_effects = true,  .n_args = 0, .func = fn_getln, },
 	};
 	IRToks ir = parse(&tokens, funcs, sizeof(funcs) / sizeof(funcs[0]));
 	if (err) {

runtime.c

@@ -57,6 +57,16 @@ Value eval_binary(IRInstr instr, const Value *lhs, const Value *rhs) {
 					case IRLe: res = lhs->Float <= rhs->Float; break;
 					default: ASSERT_UNREACHED();
 				};
+			} else if (lhs->type.kind == TypeArr && lhs->Arr.type.kind == TypeChar && lhs->Arr.is_string &&
+					rhs->type.kind == TypeArr && rhs->Arr.type.kind == TypeChar && rhs->Arr.is_string) {
+				switch (instr) {
+					case IREq:
+						res = lhs->Arr.len == rhs->Arr.len ? strncmp(lhs->Arr.vals, rhs->Arr.vals, lhs->Arr.len) == 0 : false;
+						break;
+					default:
+						set_err("String operation '%s' not supported", irinstr_str[instr]);
+						break;
+				};
 			} else {
 				set_err("Unsupported types for operation '%s': %s and %s", irinstr_str[instr], type_str[lhs->type.kind], type_str[rhs->type.kind]);
 				return (Value){0};