Content
A variable can store a specified type of value e.g. int, string, bool. This type cannot be changed later in the program.
An array can be declared from every base data type e.g. int, string, bool.
Syntax
dataType[] variableName = value;Example
str[] strs = []; # Empty string array
int[] ints = [43, 44]; # Integer array with values
ints[0] = 42; # Change value at index 0 to 42
ints[] = 45; # Append array with new value 45A boolean variable can only store the values true and false.
Example
bool b = false;
b = true;An integer variable can store values between -2^63 and 2^63-1 on 64-bit computers.
Example
int i = 42;
i = 48 / 2;A string variable can store a string value. The limit of long a string can be depends on the environment where the bash script will be executed.
Example
str s = "Hello ";
s += "World";Two values can be compared with a boolean as return value. This way the result of the comparison can be used in a condition of an if or while control structure.
The comparison of boolean values allows the equal and unequal operation.
Example
bool b = true;
# Equal
if (b == false) {
}
# Unequal
if (b != true) {
}The comparison of integer values allows the equal, unequal, greater (or equal) and smaller (or equal) operation.
Example
int i = 42;
# Equal
if (i == 48) {
}
# Unequal
if (i != 48) {
}
# Smaller
if (i < 48) {
}
# Smaller or equal
if (i <= 48) {
}
# Greater
if (i > 48) {
}
# Greater or equal
if (i >= 48) {
}The comparison of string values allows the equal, unequal, greater and smaller operation.
Example
str s = "abc";
# Equal
if (s == "abc") {
}
# Unequal
if (s != "abc") {
}
# Smaller
if (s < "bcd") {
}
# Greater
if (s > "bcd") {
}Control structures allow to change a purely linear program flow e.g. to "branches" (if) depending on a condition or repeat a code block multiple times until a condition is true (while).
The for loop executes the block of code for each array entry.
Syntax
for (type variableName in array) {
# block of code that is executed for each array entry
}Example
for (int i in [1, 2, 3]) {
printLn(i);
}
int[] ints = [4, 5, 6];
for (int i in ints) {
printLn(i);
}Use the if statement to execute a specified block of code if a condition is true.
Syntax
if (condition) {
# block of code that is executed if condition is true
}Examples
if (true) {
printLn("true");
} else if (true && true) {
printLn("true");
}
if (42 > 13) {
printLn("true");
} else {
printLn("false");
}
bool b = true;
if (b) {
printLn("true");
}The while loop executes the block of code until the given condition is true.
Syntax
while (condition) {
# block of code that is executed repeatedly while the condition is true
}Example
while (true && true) {
printLn("true");
}
int i = 0;
while (i < 10) {
i += 1;
}
bool b = true;
while (b) {
printLn("true");
}The following functions are provided for use in your scripts. These are directly transpiled into bash or represented by a function implemented in bash.
The native function exec allows to directly add bash code into the transpilat. The output from the given command is returned.
Syntax
exec(str command) strExample
exec("touch test.txt");
str cmd = "touch test.txt";
exec(cmd);The native function exit exits the current script with a status code.
Syntax
exit(int code) voidExample
exit(0); # Success
exit(1); # ErrorThe native function input waits for the user of the script to input a string and returns it.
Syntax
input(str prompt) strExample
str userInput = input("Pleas enter your name:");The native functions print and printLn write the given values to terminal. The difference between print and printLn is that printLn adds new line.
Syntax
print(str|int|bool value, ...) void
printLn(str|int|bool value, ...) voidExample
print("Hello ");
printLn("World");
printLn("str", 42, false, null);
int i = 43;
printLn("i =", i);The native function sleep waits for the given amount of seconds. After that the program flow continues.
Syntax
sleep(int seconds) voidExample
# Sleep for 10 seconds
sleep(10);The native function strContains checks if the given string contains the given substring.
Syntax
strContains(str value, str substring) boolExample
strContains("cow, pig, chicken", "pig"); # true
strContains("cow, pig, chicken", "bird"); # falseThe native function strIsBool checks if the given string is a boolean so that it could be converted to a string e.g. with strToBool.
Syntax
strIsBool(str value) boolExample
strIsBool("true"); # true
strIsBool("str"); # falseThe native function strIsInt checks if the given string is a number so that it could be converted to a string e.g. with strToInt.
Syntax
strIsInt(str value) boolExample
strIsInt("123"); # true
strIsInt("str"); # falseThe native function strSplit splits the given string at the given seperator and returns the string parts as a string array.
Syntax
strSplit(str value, str separator) str[]Example
str[] strs = strSplit("a,b,c,d", ","); # ["a", "b", "c", "d"]
strs = strSplit(exec("docker ps"), " "); # ["CONTAINER", "ID", "IMAGE", "COMMAND", "CREATED", "STATUS", "PORTS", "NAMES"]The native function strToBool takes a given string and tries to convert it into a boolean value.
Syntax
strToBool(str value) boolExample
str s = "123";
bool b1 = strToBool(s); # b = false
bool b2 = strTobool("true") # b = true
bool b3 = strTobool("false") # b = falseThe native function strToInt takes a given string and tries to convert it into an integer value.
Syntax
strToInt(str value) intExample
str s = "123";
int i = strToInt(s); # i = 123A function can be used to reuse code and make it easier to read.
Syntax
func functionName(type param) type {
# block of code executed when the function is called
}A function can be defined without parameters.
Example
func printHelloWorld() void {
printLn("Hello World!");
}
printHelloWorld();The parameters must have a fixed type e.g. int, str, bool.
Example
func printGivenString(str s) void {
printLn("Given string: '" + s + "'");
}
printGivenString("Hello World");A function can return a value. The type of the value must be fixed e.g. int, str, bool.
Example
func add(int a, int b) int {
return a + b;
}
int c = add(123, 456);