example http parser
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cozis
@@ -0,0 +1,346 @@
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scan = import("scan.noja");
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newScanner = scan.newScanner;
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Scanner = scan.Scanner;
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hint = scan.hint;
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consume = scan.consume;
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current = scan.current;
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consumeSpaces = scan.consumeSpaces;
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isDigit = scan.isDigit;
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fun parseString(scan: Scanner) {
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assert(current(scan) == '"');
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consume(scan); # Consume the opening "
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temp = "";
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char = current(scan);
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while char != '"' and char != none: {
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temp = string.cat(temp, char);
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consume(scan);
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char = current(scan);
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}
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if char == none: {
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val = none;
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err = "Source ended inside a string literal";
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} else {
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assert(char == '"');
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consume(scan);
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val = temp;
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err = none;
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}
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return val, err;
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}
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fun parseObject(scan: Scanner) {
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assert(current(scan) == '{');
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consume(scan);
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obj = {};
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consumeSpaces(scan);
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if current(scan) != '}': do {
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key, err = parseValue(scan);
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if err != none:
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return none, err;
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if type(key) != String:
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return none, "Object key isn't a string";
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consumeSpaces(scan);
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if current(scan) != ':':
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return none, "Missing ':' separator after key";
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consume(scan);
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val, err = parseValue(scan);
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if err != none:
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return none, err;
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if obj[key] != none:
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return none, "Duplicate key in object";
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obj[key] = val;
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consumeSpaces(scan);
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if current(scan) == '}':
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done = true;
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else {
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if current(scan) != ',':
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return none, "Invalid character where either ',' or '}' were expected";
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consume(scan); # Consume the ","
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done = false;
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}
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} while not done;
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assert(current(scan) == '}');
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consume(scan);
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return obj;
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}
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fun parseArray(scan: Scanner) {
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assert(current(scan) == '[');
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consume(scan); # Consume the [
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array = [];
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consumeSpaces(scan);
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if current(scan) != ']': do {
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val, err = parseValue(scan);
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if err != none:
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return none, err;
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array[count(array)] = val;
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consumeSpaces(scan);
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if current(scan) == ']':
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done = true;
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else {
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if current(scan) != ',':
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return none, "Invalid character where either ',' or ']' were expected";
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consume(scan); # Consume the ","
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done = false;
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}
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} while not done;
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assert(current(scan) == ']');
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consume(scan);
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return array;
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}
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fun parseFalse(scan: Scanner) {
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assert(current(scan) == 'f');
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consume(scan);
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if current(scan) != 'a':
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return none, "Invalid character after 'f'";
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consume(scan);
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if current(scan) != 'l':
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return none, "Invalid character after 'fa'";
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consume(scan);
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if current(scan) != 's':
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return none, "Invalid character after 'fal'";
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consume(scan);
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if current(scan) != 'e':
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return none, "Invalid character after 'fals'";
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consume(scan);
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return false;
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}
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fun parseTrue(scan: Scanner) {
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assert(current(scan) == 't');
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consume(scan);
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if current(scan) != 'r':
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return none, "Invalid character after 't'";
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consume(scan);
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if current(scan) != 'u':
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return none, "Invalid character after 'tr'";
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consume(scan);
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if current(scan) != 'e':
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return none, "Invalid character after 'tru'";
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consume(scan);
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return true;
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}
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fun parseNull(scan: Scanner) {
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assert(current(scan) == 'n');
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consume(scan);
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if current(scan) != 'u':
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return none, "Invalid character after 'n'";
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consume(scan);
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if current(scan) != 'l':
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return none, "Invalid character after 'nu'";
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consume(scan);
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if current(scan) != 'l':
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return none, "Invalid character after 'nul'";
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consume(scan);
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return none;
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}
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fun integerFromDigit(char: String) {
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assert(count(char) == 1);
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return string.ord(char)
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- string.ord('0');
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}
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fun parseNumber(scan: Scanner) {
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char = current(scan);
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sign = 1;
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if char == '+' or char == '-': {
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sign = {'+': 1, '-': -1}[char];
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consume(scan);
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char = current(scan);
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if not isDigit(char):
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return none, "Invalid character after +/-";
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}
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temp = 0.0;
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do {
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assert(isDigit(char));
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n = integerFromDigit(char);
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temp = temp * 10 + n;
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consume(scan);
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char = current(scan);
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} while isDigit(char);
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if char == '.' and isDigit(hint(scan, 1)): {
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consume(scan); # Consume the dot
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char = current(scan);
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q = 1.0;
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do {
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q = q / 10;
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n = integerFromDigit(char);
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temp = temp + q * n;
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consume(scan);
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char = current(scan);
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} while isDigit(char);
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}
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return sign * temp;
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}
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fun parseValue(scan: Scanner) {
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table = {
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'"': parseString,
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'{': parseObject,
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'[': parseArray,
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'f': parseFalse,
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't': parseTrue,
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'n': parseNull,
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'+': parseNumber,
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'-': parseNumber,
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'0': parseNumber,
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'1': parseNumber,
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'2': parseNumber,
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'3': parseNumber,
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'4': parseNumber,
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'5': parseNumber,
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'6': parseNumber,
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'7': parseNumber,
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'8': parseNumber,
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'9': parseNumber
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};
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consumeSpaces(scan);
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char = current(scan);
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if char == none: {
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val = none;
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err = "Source ended where a value was expected";
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} else {
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callback = table[char];
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if callback == none: {
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val = none;
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err = "Invalid character where a value was expected";
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} else
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(val, err) = callback(scan);
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}
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return (val, err);
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}
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fun parse(src: String) {
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scan = newScanner(src);
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val, err = parseValue(scan);
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return val, err;
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}
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fun test() {
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compareAny = import("compare.noja").compareAny;
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Error = String;
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JSONValueType = (bool | float | String | Map | List | None);
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TestCase = [String, ?JSONValueType, ?Error];
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fun runAllTestCases(test_cases: List) {
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total = count(test_cases);
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passed = 0;
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evaluated = 0;
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while evaluated < total: {
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test_case = test_cases[evaluated];
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input = test_case[0];
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expres = test_case[1]; # Expected result
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experr = test_case[2]; # Expected error
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res, err = parse(input);
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#print("res=", res, ", err=", err, "\n");
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#print("expres=", expres, ", experr=", experr, "\n");
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result = compareAny(res, expres)
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and compareAny(err, experr);
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if result: {
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print("Test ", evaluated, ": PASSED\n");
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passed = passed+1;
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} else {
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print("Test ", evaluated, ": FAILED\n");
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print("\tInput:\n");
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print("\t\t", input, "\n");
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if experr == none: {
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if err == none:
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print("\tGot result ", res, " but was expected ", expres, "\n");
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else
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print("\tFailed unexpectedly [", err, "]\n");
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} else if err == none:
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print("\tSucceded unexpectedly. Was expected error [", experr, "]\n");
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else
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print("\tWas expected error [", experr, "], but got [", err, "]\n");
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}
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evaluated = evaluated+1;
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}
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return passed, (total-passed), total;
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}
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fun newPassingTestCase(src: String, res: JSONValueType)
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return [src, res, none];
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fun newFailingTestCase(src: String, err: String)
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return [src, none, err];
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test_cases = [
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newPassingTestCase("null", none),
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newPassingTestCase("true", true),
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newPassingTestCase("false", false),
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newPassingTestCase("\"Hello, world!\"", "Hello, world!"),
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newPassingTestCase("1", 1.0),
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newPassingTestCase("2.3", 2.3),
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newPassingTestCase("[]", []),
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newPassingTestCase("[1]", [1.0]),
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newPassingTestCase("[1, 2]", [1.0, 2.0]),
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newPassingTestCase("[1, 2, 3]", [1.0, 2.0, 3.0]),
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newPassingTestCase("{}", {}),
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newPassingTestCase("{\"k1\": true}", {k1: true}),
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newPassingTestCase("{\"k1\": true, \"k2\": false}", {k1: true, k2: false})
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];
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passed, failed, total = runAllTestCases(test_cases);
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print("passed: ", passed, "\n");
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print("failed: ", failed, "\n");
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print(" total: ", total, "\n");
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}
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