doc/basics.js
// Euresys GenApi Script uses a syntax inspired by JavaScript, but is not
// exactly JavaScript. Using the extension .js for scripts is just a way to get
// proper syntax highlighting in text editors.
//
// This file describes the basics of Euresys GenApi Script. It can be executed
// by running 'gentl script <path-to-coaxlink-scripts-dir>/doc/basics.js', or
// more simply 'gentl script coaxlink://doc/basics.js'.
// Euresys GenApi Script is case-sensitive.
// Statements are always separated by semicolons (JavaScript is more
// permissive).
// Single-line comment
/* Multi-line comment
(cannot be nested)
*/
// Function declaration
function multiply(a, b) {
return a * b;
}
// Functions can be nested
function sumOfSquares(a, b) {
function square(x) {
return x * x;
}
return square(a) + square(b);
}
// Variable declaration
function Variables() {
var x = 1; // 1
var y = 2 * x; // 2
var z; // undefined
}
// Data types
function DataTypes() {
// Primitive types: Boolean, Number, String, undefined
function Booleans() {
var x = true;
var y = false;
}
function Numbers() {
var x = 3.14159;
var y = -1;
var z = 6.022e23;
}
function Strings() {
var empty = "";
var x = "euresys";
var y = 'coaxlink';
}
function Undefined() {
// undefined is the type of variables without a value
// undefined is also a special value
var x; // undefined
x = 1; // x has a value
x = undefined; // x is now again undefined
}
// Objects: Object (unordered set of key/value pairs), Array (ordered list
// of values), RegExp (regular expression)
function Objects() {
// Construction
var empty = {};
var x = { a: 1, b: 2, c: 3 };
var y = { other: x };
// Access to object properties
var sum1 = x.a + x.b + x.c; // dot notation
var sum2 = x['a'] + x['b'] + x['c']; // bracket notation
// Adding properties
x.d = 4; // x: { a: 1, b: 2, c: 3, d: 4 }
x["e"] = 5; // x: { a: 1, b: 2, c: 3, d: 4, e: 5 }
}
function Arrays() {
// Construction
var empty = [];
var x = [3.14159, 2.71828];
var mix = [1, false, "abc", {}];
// Access to array elements
var sum = x[0] + x[1]; // bracket notation
// Adding elements
x[2] = 1.61803; // x: [3.14159, 2.71828, 1.61803]
x[4] = 1.41421; // x: [3.14159, 2.71828, 1.61803, undefined, 1.41421];
}
function RegularExpressions() {
var x = /CXP[36]_X[124]/;
}
}
// Like JavaScript, Euresys GenApi Script is a dynamically typed language. The
// type of a variable is defined by the value it holds, which can change.
function DynamicVariables() {
var x = 1; // Number
x = "x is now a string";
}
// Object types are accessed by reference.
function References() {
var x = [3.14159, 2.71828]; // x is a reference to an array
var y = x; // y is a reference to the same array
assertEqual(x.length, y.length);
assertEqual(x[0], y[0]);
assertEqual(x[1], y[1]);
y[2] = 1.61803; // the array can be modified via any reference
assertEqual(x[2], y[2]);
function update(obj) {
// objects (including arrays) are passed by reference
obj.updated = true;
obj.added = true;
}
var z = { initialized: true, updated: false };
assertEqual(true, z.initialized);
assertEqual(false, z.updated);
assertEqual(undefined, z.added);
update(z);
assertEqual(true, z.initialized);
assertEqual(true, z.updated);
assertEqual(true, z.added);
}
// Supported operators
function Operators() {
// From lowest to highest precedence:
// Assignment operators: = += -= *= /=
var x = 3;
x += 2;
x -= 1;
x *= 3;
x /= 5;
assertEqual(2.4, x);
// Logical OR: ||
assertEqual(true, false || true);
assertEqual('ok', false || 'ok');
assertEqual('ok', 'ok' || 'ignored');
// Logical AND: &&
assertEqual(false, true && false);
assertEqual(true, true && true);
assertEqual('ok', true && 'ok');
// Identity (strict equality) and non-identity (strict inequality): === !==
assertEqual(true, 1 === 2 / 2);
assertEqual(true, 1 !== 2);
// Equality (==) and inequality (!=) JavaScript operators lead to confusing
// and inconsistent conversions of their operands. They are not implemented
// in Euresys GenApi Script.
// Relational operators: < <= > >=
assert(1 < 2);
assert(1 <= 1);
assert(2 > 1);
assert(2 >= 2);
// Addition and subtraction: + -
assertEqual(1, 3 - 2);
assertEqual(5, 2 + 3);
assertEqual("abcdef", "abc" + "def"); // if one of the operands is of type
assertEqual("abc123", "abc" + 123); // string, all operands are converted
assertEqual("123456", 123 + "456"); // to string, and concatenated
// Multiplication and division: * /
assertEqual(4.5, 3 * 3 / 2);
// Prefix operators: ++ -- ! typeof
var x = 0;
assertEqual(1, ++x);
assertEqual(1, x);
assertEqual(0, --x);
assertEqual(0, x);
assertEqual(true, !false);
assertEqual('boolean', typeof false);
assertEqual('number', typeof 0);
assertEqual('string', typeof '');
assertEqual('undefined', typeof undefined);
assertEqual('function', typeof function () {});
assertEqual('object', typeof {});
assertEqual('object', typeof []);
assertEqual('object', typeof /re/);
assertEqual('object', typeof null);
// Postfix operators: ++ --
var x = 0;
assertEqual(0, x++);
assertEqual(1, x);
assertEqual(1, x--);
assertEqual(0, x);
// Function call: ()
assertEqual(6, multiply(3, 2));
// Member access: . []
var obj = { a: 1 };
assertEqual(1, obj.a);
obj['4'] = 'four';
assertEqual('four', obj[2*2]);
}
// Scope of variables
function OuterFunction() {
var x = 'outer x';
function Shadowing() {
assertEqual(undefined, x);
var x = 'inner x';
assertEqual('inner x', x);
}
function Nested() {
assertEqual('outer x', x);
var y = 'not accessible outside Nested';
x += ' changed in Nested';
}
function NoBlockScope() {
var x = 1;
assertEqual(1, x);
if (true) {
// The scope of variables is the function.
// This variable x is the same as the one outside the if block.
var x = 2;
}
assertEqual(2, x);
}
assertEqual('outer x', x);
Shadowing();
assertEqual('outer x', x);
Nested();
assertEqual('outer x changed in Nested', x);
NoBlockScope();
}
// Loops
function Loops() {
// for loops
function ForLoops() {
var i;
var sum = 0;
for (i = 0; i < 6; ++i) {
sum += i;
}
assertEqual(15, sum);
}
// for..in loops: iterating over indices
function ForInLoops() {
var xs = [1, 10, 100, 1000];
var sum = 0;
for (var i in xs) {
sum += xs[i];
}
assertEqual(1111, sum);
var obj = { one: 1, two: 2 };
var sum = 0;
for (var p in obj) {
sum += obj[p];
}
assertEqual(3, sum);
var str = "Coaxlink";
var sum = "";
for (var i in str) {
sum += str[i];
}
assertEqual("Coaxlink", sum);
}
// for..of loops: iterating over values
function ForOfLoops() {
var xs = [1, 10, 100, 1000];
var sum = 0;
for (var x of xs) {
sum += x;
}
assertEqual(1111, sum);
var obj = { one: 1, two: 2 };
var sum = 0;
for (var x of obj) {
sum += x;
}
assertEqual(3, sum);
var str = "Coaxlink";
var sum = "";
for (var c of str) {
sum += c;
}
assertEqual("Coaxlink", sum);
}
function ContinueAndBreak() {
var i;
var sum = 0;
for (i = 0; i < 100; ++i) {
if (i === 3) {
continue;
} else if (i === 6) {
break;
} else {
sum += i;
}
}
assertEqual(0 + 1 + 2 + 4 + 5, sum);
}
ForLoops();
ForInLoops();
ForOfLoops();
ContinueAndBreak();
}
function Exceptions() {
var x;
var caught;
var finallyDone;
function f(action) {
x = 0;
caught = undefined;
finallyDone = false;
try {
x = 1;
if (action === 'fail') {
throw action;
} else if (action === 'return') {
return;
}
x = 2;
} catch (e) {
// Executed if a throw statement is executed.
assertEqual(1, x);
caught = e;
} finally {
// Executed regardless of whether or not a throw statement is
// executed. Also executed if a return statement causes the
// function to exit before the end of the try block.
finallyDone = true;
}
}
f('fail');
assertEqual(1, x);
assertEqual('fail', caught);
assert(finallyDone);
f('return');
assertEqual(1, x);
assert(!caught);
assert(finallyDone);
f();
assertEqual(2, x);
assert(!caught);
assert(finallyDone);
}
// Run tests
References();
Operators();
OuterFunction();
Loops();
Exceptions();
function assertEqual(expected, actual) {
if (expected !== actual) {
throw 'expected: ' + expected + ', actual: ' + actual;
}
}
function assert(condition) {
if (!condition) {
throw 'failed assertion';
}
}
About Euresys Documentation
This documentation is optimized for Google Chrome from version 44, and Microsoft Edge from version 20.
It needs Javascript to display properly. Your browser must enable active scripting.
The recommended screen resolution is at least 1280 x 1024.
This documentation is provided with Coaxlink 10.3 (doc build 2052).
Terms of Use
EURESYS s.a. shall retain all property rights, title and interest of the documentation of the hardware and the software, and of the trademarks of EURESYS s.a.
All the names of companies and products mentioned in the documentation may be the trademarks of their respective owners.
The licensing, use, leasing, loaning, translation, reproduction, copying or modification of the hardware or the software, brands or documentation of EURESYS s.a. contained in this book, is not allowed without prior notice.
EURESYS s.a. may modify the product specification or change the information given in this documentation at any time, at its discretion, and without prior notice.
EURESYS s.a. shall not be liable for any loss of or damage to revenues, profits, goodwill, data, information systems or other special, incidental, indirect, consequential or punitive damages of any kind arising in connection with the use of the hardware or the software of EURESYS s.a. or resulting of omissions or errors in this documentation.
