add demo examples

examples/example_performance.slg

@@ -0,0 +1,106 @@
+
+fn main() {
+    for (let i = 0; i < 100; i += 1) {
+        string_to_int_impl("497");
+        string_to_int_impl("0b1001100000");
+        string_to_int_impl("0");
+        string_to_int_impl("0x9f");
+        string_to_int_impl("055");
+        string_to_int_impl("0b1000000");
+        string_to_int_impl("0b101111101");
+        string_to_int_impl("271");
+        string_to_int_impl("0x2bd");
+        string_to_int_impl("0x31e");
+        string_to_int_impl("0b1001101111");
+        string_to_int_impl("0535");
+        string_to_int_impl("0x233");
+        string_to_int_impl("01622");
+        string_to_int_impl("0");
+        string_to_int_impl("0b10001010");
+        string_to_int_impl("0b1111001101");
+        string_to_int_impl("0x93");
+        string_to_int_impl("0x23e");
+        string_to_int_impl("0316");
+    }
+}
+
+fn string_to_int_impl(text: string) -> int {
+    let base_2_digits = "01";
+    let base_8_digits = base_2_digits + "234567";
+    let base_10_digits = base_8_digits + "89";
+    let base_16_digits = base_10_digits + "abcdef";
+
+    let len = string_length(text);
+    if len == 0 {
+        return -1;
+    }
+    if text[0] == "0"[0] {
+        if len == 1 {
+            0
+        } else if text[1] == "b"[0] {
+            parse_digits(string_slice(text, 2, -1), 2, base_2_digits)
+        } else if text[1] == "x"[0] {
+            parse_digits(string_slice(text, 2, -1), 16, base_16_digits)
+        } else {
+            parse_digits(string_slice(text, 1, -1), 8, base_8_digits)
+        }
+    } else {
+        parse_digits(text, 10, base_10_digits)
+    }
+}
+
+fn parse_digits(text: string, base: int, digit_set: string) -> int {
+    let val = 0;
+    let len = string_length(text);
+    for (let i = 0; i < len; i += 1) {
+        let ch = text[i];
+        if not string_contains(digit_set, ch) {
+            return -1;
+        }
+        val = val * base;
+        val += char_val(ch);
+    }
+    val
+}
+
+fn char_val(ch: int) -> int {
+    if ch >= "0"[0] and ch <= "9"[0] {
+        ch - "0"[0]
+    } else if ch >= "a"[0] and ch <= "f"[0] {
+        ch - "a"[0] + 10
+    } else {
+        -1
+    }
+}
+
+fn string_slice(str: string, from: int, to: int) -> string {
+    let result = "";
+    let len = string_length(str);
+    let abs_to =
+        if to >= len { len }
+        else if to < 0 { len + to + 1 }
+        else { to };
+    for (let i = from; i < abs_to; i += 1) {
+        result = string_push_char(result, str[i]);
+    }
+    result
+}
+
+fn string_contains(str: string, ch: int) -> bool {
+    let len = string_length(str);
+    for (let i = 0; i < len; i += 1) {
+        if str[i] == ch {
+            return true;
+        }
+    }
+    false
+}
+
+fn print(msg: string) #[builtin(Print)] {}
+fn println(msg: string) { print(msg + "\n") }
+
+fn string_push_char(str: string, value: int) -> string #[builtin(StringPushChar)] {}
+fn string_length(str: string) -> int #[builtin(StringLength)] {}
+
+fn itos(number: int) -> string #[builtin(IntToString)] {}
+

examples/example_test_coverage.slg

@@ -0,0 +1,111 @@
+
+fn main() {
+    let ok = test_string_to_int_impl();
+    if not ok {
+        println("tests failed!");
+    }
+}
+
+fn test_string_to_int_impl() -> bool {
+        test("should convert zero",      assert_int_equal(string_to_int_impl("0"), 0))
+    and test("should convert decimal",   assert_int_equal(string_to_int_impl("10"), 10))
+    and test("should convert binary",    assert_int_equal(string_to_int_impl("0b110"), 6))
+    and test("should convert octal",     assert_int_equal(string_to_int_impl("071"), 57))
+    // and test("should convert hex",       assert_int_equal(string_to_int_impl("0xaa"), 170))
+    and test("should fail",              assert_int_equal(string_to_int_impl("john"), -1))
+    // and test("should fail",              assert_int_equal(string_to_int_impl(""), -1))
+}
+
+fn assert_int_equal(value: int, target: int) -> bool {
+    if value != target {
+        println("assertion failed: " + itos(value) + " != " + itos(target));
+        return false;
+    }
+    true
+}
+
+fn test(name: string, assertion: bool) -> bool {
+    println(" * test: " + name + " -> " + if assertion { "ok" } else { "failed" });
+    assertion
+}
+
+fn string_to_int_impl(text: string) -> int {
+    let base_2_digits = "01";
+    let base_8_digits = base_2_digits + "234567";
+    let base_10_digits = base_8_digits + "89";
+    let base_16_digits = base_10_digits + "abcdef";
+
+    let len = string_length(text);
+    if len == 0 {
+        return -1;
+    }
+    if text[0] == "0"[0] {
+        if len == 1 {
+            0
+        } else if text[1] == "b"[0] {
+            parse_digits(string_slice(text, 2, -1), 2, base_2_digits)
+        } else if text[1] == "x"[0] {
+            parse_digits(string_slice(text, 2, -1), 16, base_16_digits)
+        } else {
+            parse_digits(string_slice(text, 1, -1), 8, base_8_digits)
+        }
+    } else {
+        parse_digits(text, 10, base_10_digits)
+    }
+}
+
+fn parse_digits(text: string, base: int, digit_set: string) -> int {
+    let val = 0;
+    let len = string_length(text);
+    for (let i = 0; i < len; i += 1) {
+        let ch = text[i];
+        if not string_contains(digit_set, ch) {
+            return -1;
+        }
+        val = val * base;
+        val += char_val(ch);
+    }
+    val
+}
+
+fn char_val(ch: int) -> int {
+    if ch >= "0"[0] and ch <= "9"[0] {
+        ch - "0"[0]
+    } else if ch >= "a"[0] and ch <= "f"[0] {
+        ch - "a"[0] + 10
+    } else {
+        -1
+    }
+}
+
+fn string_slice(str: string, from: int, to: int) -> string {
+    let result = "";
+    let len = string_length(str);
+    let abs_to =
+        if to >= len { len }
+        else if to < 0 { len + to + 1 }
+        else { to };
+    for (let i = from; i < abs_to; i += 1) {
+        result = string_push_char(result, str[i]);
+    }
+    result
+}
+
+fn string_contains(str: string, ch: int) -> bool {
+    let len = string_length(str);
+    for (let i = 0; i < len; i += 1) {
+        if str[i] == ch {
+            return true;
+        }
+    }
+    false
+}
+
+fn print(msg: string) #[builtin(Print)] {}
+fn println(msg: string) { print(msg + "\n") }
+
+fn string_push_char(str: string, value: int) -> string #[builtin(StringPushChar)] {}
+fn string_length(str: string) -> int #[builtin(StringLength)] {}
+
+fn itos(number: int) -> string #[builtin(IntToString)] {}
+