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JavaScript

"use strict";
let chai = require("chai");
let parser = require("../../lib/parser");
let expect = chai.expect;
describe("PEG.js grammar parser", function() {
let literalAbcd = { type: "literal", value: "abcd", ignoreCase: false };
let literalEfgh = { type: "literal", value: "efgh", ignoreCase: false };
let literalIjkl = { type: "literal", value: "ijkl", ignoreCase: false };
let literalMnop = { type: "literal", value: "mnop", ignoreCase: false };
let semanticAnd = { type: "semantic_and", code: " code " };
let semanticNot = { type: "semantic_not", code: " code " };
let optional = { type: "optional", expression: literalAbcd };
let zeroOrMore = { type: "zero_or_more", expression: literalAbcd };
let oneOrMore = { type: "one_or_more", expression: literalAbcd };
let textOptional = { type: "text", expression: optional };
let simpleNotAbcd = { type: "simple_not", expression: literalAbcd };
let simpleAndOptional = { type: "simple_and", expression: optional };
let simpleNotOptional = { type: "simple_not", expression: optional };
let labeledAbcd = { type: "labeled", label: "a", expression: literalAbcd };
let labeledEfgh = { type: "labeled", label: "b", expression: literalEfgh };
let labeledIjkl = { type: "labeled", label: "c", expression: literalIjkl };
let labeledMnop = { type: "labeled", label: "d", expression: literalMnop };
let labeledSimpleNot = { type: "labeled", label: "a", expression: simpleNotAbcd };
let sequence = {
type: "sequence",
elements: [literalAbcd, literalEfgh, literalIjkl]
};
let sequence2 = {
type: "sequence",
elements: [labeledAbcd, labeledEfgh]
};
let sequence4 = {
type: "sequence",
elements: [labeledAbcd, labeledEfgh, labeledIjkl, labeledMnop]
};
let groupLabeled = { type: "group", expression: labeledAbcd };
let groupSequence = { type: "group", expression: sequence };
let actionAbcd = { type: "action", expression: literalAbcd, code: " code " };
let actionEfgh = { type: "action", expression: literalEfgh, code: " code " };
let actionIjkl = { type: "action", expression: literalIjkl, code: " code " };
let actionMnop = { type: "action", expression: literalMnop, code: " code " };
let actionSequence = { type: "action", expression: sequence, code: " code " };
let choice = {
type: "choice",
alternatives: [literalAbcd, literalEfgh, literalIjkl]
};
let choice2 = {
type: "choice",
alternatives: [actionAbcd, actionEfgh]
};
let choice4 = {
type: "choice",
alternatives: [actionAbcd, actionEfgh, actionIjkl, actionMnop]
};
let named = { type: "named", name: "start rule", expression: literalAbcd };
let ruleA = { type: "rule", name: "a", expression: literalAbcd };
let ruleB = { type: "rule", name: "b", expression: literalEfgh };
let ruleC = { type: "rule", name: "c", expression: literalIjkl };
let ruleStart = { type: "rule", name: "start", expression: literalAbcd };
let initializer = { type: "initializer", code: " code " };
function oneRuleGrammar(expression) {
return {
type: "grammar",
imports: [],
initializer: null,
rules: [{ type: "rule", name: "start", expression: expression }]
};
}
function actionGrammar(code) {
return oneRuleGrammar(
{ type: "action", expression: literalAbcd, code: code }
);
}
function literalGrammar(value, ignoreCase) {
return oneRuleGrammar(
{ type: "literal", value: value, ignoreCase: ignoreCase }
);
}
function classGrammar(parts, inverted, ignoreCase) {
return oneRuleGrammar({
type: "class",
parts: parts,
inverted: inverted,
ignoreCase: ignoreCase
});
}
function anyGrammar() {
return oneRuleGrammar({ type: "any" });
}
function ruleRefGrammar(name) {
return oneRuleGrammar({ type: "rule_ref", name: name });
}
let trivialGrammar = literalGrammar("abcd", false);
let twoRuleGrammar = {
type: "grammar",
imports: [],
initializer: null,
rules: [ruleA, ruleB]
};
let stripLocation = (function() {
function buildVisitor(functions) {
return function(node) {
return functions[node.type].apply(null, arguments);
};
}
function stripLeaf(node) {
delete node.location;
}
function stripExpression(node) {
delete node.location;
strip(node.expression);
}
function stripChildren(property) {
return function(node) {
delete node.location;
node[property].forEach(strip);
};
}
let strip = buildVisitor({
grammar(node) {
delete node.location;
if (node.initializer) {
strip(node.initializer);
}
node.rules.forEach(strip);
},
initializer: stripLeaf,
rule: stripExpression,
named: stripExpression,
choice: stripChildren("alternatives"),
action: stripExpression,
sequence: stripChildren("elements"),
labeled: stripExpression,
text: stripExpression,
simple_and: stripExpression,
simple_not: stripExpression,
optional: stripExpression,
zero_or_more: stripExpression,
one_or_more: stripExpression,
group: stripExpression,
semantic_and: stripLeaf,
semantic_not: stripLeaf,
rule_ref: stripLeaf,
literal: stripLeaf,
class: stripLeaf,
any: stripLeaf
});
return strip;
})();
function helpers(chai, utils) {
let Assertion = chai.Assertion;
Assertion.addMethod("parseAs", function(expected) {
let result = parser.parse(utils.flag(this, "object"));
stripLocation(result);
this.assert(
utils.eql(result, expected),
"expected #{this} to parse as #{exp} but got #{act}",
"expected #{this} to not parse as #{exp}",
expected,
result,
!utils.flag(this, "negate")
);
});
Assertion.addMethod("failToParse", function(props) {
let passed, result;
try {
result = parser.parse(utils.flag(this, "object"));
passed = true;
} catch (e) {
result = e;
passed = false;
}
if (passed) {
stripLocation(result);
}
this.assert(
!passed,
"expected #{this} to fail to parse but got #{act}",
"expected #{this} to not fail to parse but it failed with #{act}",
null,
result
);
if (!passed && props !== undefined) {
Object.keys(props).forEach(key => {
new Assertion(result).to.have.property(key)
.that.is.deep.equal(props[key]);
});
}
});
}
// Helper activation needs to put inside a |beforeEach| block because the
// helpers conflict with the ones in
// test/behavior/generated-parser-behavior.spec.js.
beforeEach(function() {
chai.use(helpers);
});
// Canonical Grammar is "a = 'abcd'; b = 'efgh'; c = 'ijkl';".
it("parses Grammar", function() {
expect("\na = 'abcd';\n").to.parseAs(
{ type: "grammar", imports: [], initializer: null, rules: [ruleA] }
);
expect("\na = 'abcd';\nb = 'efgh';\nc = 'ijkl';\n").to.parseAs(
{ type: "grammar", imports: [], initializer: null, rules: [ruleA, ruleB, ruleC] }
);
expect("\n{ code };\na = 'abcd';\n").to.parseAs(
{ type: "grammar", imports: [], initializer: initializer, rules: [ruleA] }
);
});
// Canonical Initializer is "{ code }".
it("parses Initializer", function() {
expect("{ code };start = 'abcd'").to.parseAs(
{ type: "grammar", imports: [], initializer: initializer, rules: [ruleStart] }
);
});
// Canonical Rule is "a = 'abcd';".
it("parses Rule", function() {
expect("start\n=\n'abcd';").to.parseAs(
oneRuleGrammar(literalAbcd)
);
expect("start\n'start rule'\n=\n'abcd';").to.parseAs(
oneRuleGrammar(named)
);
});
// Canonical Expression is "'abcd'".
it("parses Expression", function() {
expect("start = 'abcd' / 'efgh' / 'ijkl'").to.parseAs(
oneRuleGrammar(choice)
);
});
// Canonical ChoiceExpression is "'abcd' / 'efgh' / 'ijkl'".
it("parses ChoiceExpression", function() {
expect("start = 'abcd' { code }").to.parseAs(
oneRuleGrammar(actionAbcd)
);
expect("start = 'abcd' { code }\n/\n'efgh' { code }").to.parseAs(
oneRuleGrammar(choice2)
);
expect(
"start = 'abcd' { code }\n/\n'efgh' { code }\n/\n'ijkl' { code }\n/\n'mnop' { code }"
).to.parseAs(
oneRuleGrammar(choice4)
);
});
// Canonical ActionExpression is "'abcd' { code }".
it("parses ActionExpression", function() {
expect("start = 'abcd' 'efgh' 'ijkl'").to.parseAs(
oneRuleGrammar(sequence)
);
expect("start = 'abcd' 'efgh' 'ijkl'\n{ code }").to.parseAs(
oneRuleGrammar(actionSequence)
);
});
// Canonical SequenceExpression is "'abcd' 'efgh' 'ijkl'".
it("parses SequenceExpression", function() {
expect("start = a:'abcd'").to.parseAs(
oneRuleGrammar(labeledAbcd)
);
expect("start = a:'abcd'\nb:'efgh'").to.parseAs(
oneRuleGrammar(sequence2)
);
expect("start = a:'abcd'\nb:'efgh'\nc:'ijkl'\nd:'mnop'").to.parseAs(
oneRuleGrammar(sequence4)
);
});
// Canonical LabeledExpression is "a:'abcd'".
it("parses LabeledExpression", function() {
expect("start = a\n:\n!'abcd'").to.parseAs(oneRuleGrammar(labeledSimpleNot));
expect("start = !'abcd'").to.parseAs(oneRuleGrammar(simpleNotAbcd));
});
// Canonical PrefixedExpression is "!'abcd'".
it("parses PrefixedExpression", function() {
expect("start = !\n'abcd'?").to.parseAs(oneRuleGrammar(simpleNotOptional));
expect("start = 'abcd'?").to.parseAs(oneRuleGrammar(optional));
});
// Canonical PrefixedOperator is "!".
it("parses PrefixedOperator", function() {
expect("start = $'abcd'?").to.parseAs(oneRuleGrammar(textOptional));
expect("start = &'abcd'?").to.parseAs(oneRuleGrammar(simpleAndOptional));
expect("start = !'abcd'?").to.parseAs(oneRuleGrammar(simpleNotOptional));
});
// Canonical SuffixedExpression is "'abcd'?".
it("parses SuffixedExpression", function() {
expect("start = 'abcd'\n?").to.parseAs(oneRuleGrammar(optional));
expect("start = 'abcd'").to.parseAs(oneRuleGrammar(literalAbcd));
});
// Canonical SuffixedOperator is "?".
it("parses SuffixedOperator", function() {
expect("start = 'abcd'?").to.parseAs(oneRuleGrammar(optional));
expect("start = 'abcd'*").to.parseAs(oneRuleGrammar(zeroOrMore));
expect("start = 'abcd'+").to.parseAs(oneRuleGrammar(oneOrMore));
});
// Canonical PrimaryExpression is "'abcd'".
it("parses PrimaryExpression", function() {
expect("start = 'abcd'").to.parseAs(trivialGrammar);
expect("start = [a-d]").to.parseAs(classGrammar([["a", "d"]], false, false));
expect("start = .").to.parseAs(anyGrammar());
expect("start = a").to.parseAs(ruleRefGrammar("a"));
expect("start = &{ code }").to.parseAs(oneRuleGrammar(semanticAnd));
expect("start = (\na:'abcd'\n)").to.parseAs(oneRuleGrammar(groupLabeled));
expect("start = (\n'abcd' 'efgh' 'ijkl'\n)").to.parseAs(oneRuleGrammar(groupSequence));
expect("start = (\n'abcd'\n)").to.parseAs(trivialGrammar);
});
// Canonical RuleReferenceExpression is "a".
it("parses RuleReferenceExpression", function() {
expect("start = a").to.parseAs(ruleRefGrammar("a"));
expect("start = a\n=").to.failToParse();
expect("start = a\n'abcd'\n=").to.failToParse();
});
// Canonical SemanticPredicateExpression is "!{ code }".
it("parses SemanticPredicateExpression", function() {
expect("start = !\n{ code }").to.parseAs(oneRuleGrammar(semanticNot));
});
// Canonical SemanticPredicateOperator is "!".
it("parses SemanticPredicateOperator", function() {
expect("start = &{ code }").to.parseAs(oneRuleGrammar(semanticAnd));
expect("start = !{ code }").to.parseAs(oneRuleGrammar(semanticNot));
});
// The SourceCharacter rule is not tested.
// Canonical WhiteSpace is " ".
it("parses WhiteSpace", function() {
expect("start =\t'abcd'").to.parseAs(trivialGrammar);
expect("start =\v'abcd'").to.parseAs(trivialGrammar);
expect("start =\f'abcd'").to.parseAs(trivialGrammar);
expect("start = 'abcd'").to.parseAs(trivialGrammar);
expect("start =\u00A0'abcd'").to.parseAs(trivialGrammar);
expect("start =\uFEFF'abcd'").to.parseAs(trivialGrammar);
expect("start =\u1680'abcd'").to.parseAs(trivialGrammar);
});
// Canonical LineTerminator is "\n".
it("parses LineTerminator", function() {
expect("start = '\n'").to.failToParse();
expect("start = '\r'").to.failToParse();
expect("start = '\u2028'").to.failToParse();
expect("start = '\u2029'").to.failToParse();
});
// Canonical LineTerminatorSequence is "\r\n".
it("parses LineTerminatorSequence", function() {
expect("start =\n'abcd'").to.parseAs(trivialGrammar);
expect("start =\r\n'abcd'").to.parseAs(trivialGrammar);
expect("start =\r'abcd'").to.parseAs(trivialGrammar);
expect("start =\u2028'abcd'").to.parseAs(trivialGrammar);
expect("start =\u2029'abcd'").to.parseAs(trivialGrammar);
});
// Canonical Comment is "/* comment */".
it("parses Comment", function() {
expect("start =// comment\n'abcd'").to.parseAs(trivialGrammar);
expect("start =/* comment */'abcd'").to.parseAs(trivialGrammar);
});
// Canonical MultiLineComment is "/* comment */".
it("parses MultiLineComment", function() {
expect("start =/**/'abcd'").to.parseAs(trivialGrammar);
expect("start =/*a*/'abcd'").to.parseAs(trivialGrammar);
expect("start =/*abc*/'abcd'").to.parseAs(trivialGrammar);
expect("start =/**/*/'abcd'").to.failToParse();
});
// Canonical MultiLineCommentNoLineTerminator is "/* comment */".
it("parses MultiLineCommentNoLineTerminator", function() {
expect("a = 'abcd'/**/\r\nb = 'efgh'").to.parseAs(twoRuleGrammar);
expect("a = 'abcd'/*a*/\r\nb = 'efgh'").to.parseAs(twoRuleGrammar);
expect("a = 'abcd'/*abc*/\r\nb = 'efgh'").to.parseAs(twoRuleGrammar);
expect("a = 'abcd'/**/*/\r\nb = 'efgh'").to.failToParse();
expect("a = 'abcd'/*\n*/\r\nb = 'efgh'").to.failToParse();
});
// Canonical SingleLineComment is "// comment".
it("parses SingleLineComment", function() {
expect("start =//\n'abcd'").to.parseAs(trivialGrammar);
expect("start =//a\n'abcd'").to.parseAs(trivialGrammar);
expect("start =//abc\n'abcd'").to.parseAs(trivialGrammar);
expect("start =//\n@\n'abcd'").to.failToParse();
});
// Canonical Identifier is "a".
it("parses Identifier", function() {
expect("start = a:'abcd'").to.parseAs(oneRuleGrammar(labeledAbcd));
});
// Canonical IdentifierName is "a".
it("parses IdentifierName", function() {
expect("start = a").to.parseAs(ruleRefGrammar("a"));
expect("start = ab").to.parseAs(ruleRefGrammar("ab"));
expect("start = abcd").to.parseAs(ruleRefGrammar("abcd"));
});
// Canonical IdentifierStart is "a".
it("parses IdentifierStart", function() {
expect("start = a").to.parseAs(ruleRefGrammar("a"));
expect("start = $").to.parseAs(ruleRefGrammar("$"));
expect("start = _").to.parseAs(ruleRefGrammar("_"));
expect("start = \\u0061").to.parseAs(ruleRefGrammar("a"));
});
// Canonical IdentifierPart is "a".
it("parses IdentifierPart", function() {
expect("start = aa").to.parseAs(ruleRefGrammar("aa"));
expect("start = a\u0300").to.parseAs(ruleRefGrammar("a\u0300"));
expect("start = a0").to.parseAs(ruleRefGrammar("a0"));
expect("start = a\u203F").to.parseAs(ruleRefGrammar("a\u203F"));
expect("start = a\u200C").to.parseAs(ruleRefGrammar("a\u200C"));
expect("start = a\u200D").to.parseAs(ruleRefGrammar("a\u200D"));
});
// Unicode rules and reserved word rules are not tested.
// Canonical LiteralMatcher is "'abcd'".
it("parses LiteralMatcher", function() {
expect("start = 'abcd'").to.parseAs(literalGrammar("abcd", false));
expect("start = 'abcd'i").to.parseAs(literalGrammar("abcd", true));
});
// Canonical StringLiteral is "'abcd'".
it("parses StringLiteral", function() {
expect("start = \"\"").to.parseAs(literalGrammar("", false));
expect("start = \"a\"").to.parseAs(literalGrammar("a", false));
expect("start = \"abc\"").to.parseAs(literalGrammar("abc", false));
expect("start = ''").to.parseAs(literalGrammar("", false));
expect("start = 'a'").to.parseAs(literalGrammar("a", false));
expect("start = 'abc'").to.parseAs(literalGrammar("abc", false));
});
// Canonical DoubleStringCharacter is "a".
it("parses DoubleStringCharacter", function() {
expect("start = \"a\"").to.parseAs(literalGrammar("a", false));
expect("start = \"\\n\"").to.parseAs(literalGrammar("\n", false));
expect("start = \"\\\n\"").to.parseAs(literalGrammar("", false));
expect("start = \"\"\"").to.failToParse();
expect("start = \"\\\"").to.failToParse();
expect("start = \"\n\"").to.failToParse();
});
// Canonical SingleStringCharacter is "a".
it("parses SingleStringCharacter", function() {
expect("start = 'a'").to.parseAs(literalGrammar("a", false));
expect("start = '\\n'").to.parseAs(literalGrammar("\n", false));
expect("start = '\\\n'").to.parseAs(literalGrammar("", false));
expect("start = '''").to.failToParse();
expect("start = '\\'").to.failToParse();
expect("start = '\n'").to.failToParse();
});
// Canonical CharacterClassMatcher is "[a-d]".
it("parses CharacterClassMatcher", function() {
expect("start = []").to.parseAs(
classGrammar([], false, false)
);
expect("start = [a-d]").to.parseAs(
classGrammar([["a", "d"]], false, false)
);
expect("start = [a]").to.parseAs(
classGrammar(["a"], false, false)
);
expect("start = [a-de-hi-l]").to.parseAs(
classGrammar(
[["a", "d"], ["e", "h"], ["i", "l"]],
false,
false
)
);
expect("start = [^a-d]").to.parseAs(
classGrammar([["a", "d"]], true, false)
);
expect("start = [a-d]i").to.parseAs(
classGrammar([["a", "d"]], false, true)
);
expect("start = [\\\n]").to.parseAs(
classGrammar([], false, false)
);
});
// Canonical ClassCharacterRange is "a-d".
it("parses ClassCharacterRange", function() {
expect("start = [a-d]").to.parseAs(classGrammar([["a", "d"]], false, false));
expect("start = [a-a]").to.parseAs(classGrammar([["a", "a"]], false, false));
expect("start = [b-a]").to.failToParse({
message: "Invalid character range: b-a."
});
});
// Canonical ClassCharacter is "a".
it("parses ClassCharacter", function() {
expect("start = [a]").to.parseAs(classGrammar(["a"], false, false));
expect("start = [\\n]").to.parseAs(classGrammar(["\n"], false, false));
expect("start = [\\\n]").to.parseAs(classGrammar([], false, false));
expect("start = []]").to.failToParse();
expect("start = [\\]").to.failToParse();
expect("start = [\n]").to.failToParse();
});
// Canonical LineContinuation is "\\\n".
it("parses LineContinuation", function() {
expect("start = '\\\r\n'").to.parseAs(literalGrammar("", false));
});
// Canonical EscapeSequence is "n".
it("parses EscapeSequence", function() {
expect("start = '\\n'").to.parseAs(literalGrammar("\n", false));
expect("start = '\\0'").to.parseAs(literalGrammar("\x00", false));
expect("start = '\\xFF'").to.parseAs(literalGrammar("\xFF", false));
expect("start = '\\uFFFF'").to.parseAs(literalGrammar("\uFFFF", false));
expect("start = '\\09'").to.failToParse();
});
// Canonical CharacterEscapeSequence is "n".
it("parses CharacterEscapeSequence", function() {
expect("start = '\\n'").to.parseAs(literalGrammar("\n", false));
expect("start = '\\a'").to.parseAs(literalGrammar("a", false));
});
// Canonical SingleEscapeCharacter is "n".
it("parses SingleEscapeCharacter", function() {
expect("start = '\\''").to.parseAs(literalGrammar("'", false));
expect("start = '\\\"'").to.parseAs(literalGrammar("\"", false));
expect("start = '\\\\'").to.parseAs(literalGrammar("\\", false));
expect("start = '\\b'").to.parseAs(literalGrammar("\b", false));
expect("start = '\\f'").to.parseAs(literalGrammar("\f", false));
expect("start = '\\n'").to.parseAs(literalGrammar("\n", false));
expect("start = '\\r'").to.parseAs(literalGrammar("\r", false));
expect("start = '\\t'").to.parseAs(literalGrammar("\t", false));
expect("start = '\\v'").to.parseAs(literalGrammar("\v", false));
});
// Canonical NonEscapeCharacter is "a".
it("parses NonEscapeCharacter", function() {
expect("start = '\\a'").to.parseAs(literalGrammar("a", false));
// The negative predicate is impossible to test with PEG.js grammar
// structure.
});
// The EscapeCharacter rule is impossible to test with PEG.js grammar
// structure.
// Canonical HexEscapeSequence is "xFF".
it("parses HexEscapeSequence", function() {
expect("start = '\\xFF'").to.parseAs(literalGrammar("\xFF", false));
});
// Canonical UnicodeEscapeSequence is "uFFFF".
it("parses UnicodeEscapeSequence", function() {
expect("start = '\\uFFFF'").to.parseAs(literalGrammar("\uFFFF", false));
});
// Digit rules are not tested.
// Canonical AnyMatcher is ".".
it("parses AnyMatcher", function() {
expect("start = .").to.parseAs(anyGrammar());
});
// Canonical CodeBlock is "{ code }".
it("parses CodeBlock", function() {
expect("start = 'abcd' { code }").to.parseAs(actionGrammar(" code "));
});
// Canonical Code is " code ".
it("parses Code", function() {
expect("start = 'abcd' {a}").to.parseAs(actionGrammar("a"));
expect("start = 'abcd' {abc}").to.parseAs(actionGrammar("abc"));
expect("start = 'abcd' {{a}}").to.parseAs(actionGrammar("{a}"));
expect("start = 'abcd' {{a}{b}{c}}").to.parseAs(actionGrammar("{a}{b}{c}"));
expect("start = 'abcd' {{}").to.failToParse();
expect("start = 'abcd' {}}").to.failToParse();
});
// Unicode character category rules and token rules are not tested.
// Canonical __ is "\n".
it("parses __", function() {
expect("start ='abcd'").to.parseAs(trivialGrammar);
expect("start = 'abcd'").to.parseAs(trivialGrammar);
expect("start =\r\n'abcd'").to.parseAs(trivialGrammar);
expect("start =/* comment */'abcd'").to.parseAs(trivialGrammar);
expect("start = 'abcd'").to.parseAs(trivialGrammar);
});
// Canonical _ is " ".
it("parses _", function() {
expect("a = 'abcd'\r\nb = 'efgh'").to.parseAs(twoRuleGrammar);
expect("a = 'abcd' \r\nb = 'efgh'").to.parseAs(twoRuleGrammar);
expect("a = 'abcd'/* comment */\r\nb = 'efgh'").to.parseAs(twoRuleGrammar);
expect("a = 'abcd' \r\nb = 'efgh'").to.parseAs(twoRuleGrammar);
});
// Canonical EOS is ";".
it("parses EOS", function() {
expect("a = 'abcd'\n;b = 'efgh'").to.parseAs(twoRuleGrammar);
expect("a = 'abcd' \r\nb = 'efgh'").to.parseAs(twoRuleGrammar);
expect("a = 'abcd' // comment\r\nb = 'efgh'").to.parseAs(twoRuleGrammar);
expect("a = 'abcd'\nb = 'efgh'").to.parseAs(twoRuleGrammar);
});
// Canonical EOF is the end of input.
it("parses EOF", function() {
expect("start = 'abcd'\n").to.parseAs(trivialGrammar);
});
});