BashTranspilat.md

Bash Transpilat

This document contains technical details how the structures have been solved in bash syntax.

Content

• Bool
• Bool - Assign comparison
• Function Return values

Bool

There are no native bool types in bash. So boolean expressions are represented as strings.

Example:

# ScriLa
if (true && false) {
	printLn("true");
}

# Bash transpilat
if [[ "true" == "true" ]] && [[ "false" == "true" ]]; then
	echo "true"
fi

Bool - Assign comparison

There is no native way to assign the result of a comparision as bool to a variable in bash. So this assignment will be replaced with a if statement that uses the temporary variable $tmpBool and sets it to true or false (in the else block).

Example:

# ScriLa
bool b = 42 > 13;

# Bash transpilat
if [[ 42 -gt 13 ]]
then
	tmpBools[0]="true"
else
	tmpBools[0]="false"
fi
b="${tmpBools[0]}"

Function Return values

Bash functions can return a status code between 0 and 255. Zero stands for success.
Bash Example:

# Bash
function fn() {
    return 42
}

The bash transpilat for a ScriLa function uses a temporary variable of type array to return the value:

Return type	Variable
bool	$tmpBools
int	$tmpInts
string	$tmpStrs

The index of the array is dynamic so that it can be set from outside of the function. This allows passing multiple function calls as arguments for a function call.

Example:

# ScriLa
func add(int a, int b) int {
	return a + b;
}

int result = add(13, 42);

# Bash transpilat
add () {
	local a=$1
	local b=$2
	tmpInts[${tmpIndex}]=$((${a} + ${b}))
	return
}

tmpIndex=0
add 13 42
result=${tmpInts[0]}