preprocessor-statements.md

Preprocessor statements

set statement

The set statement, sets a preprocessor variable to a value. The values of preprocessor variables are not bound to types.

%set VERSION 0.7.1%
%set APPLICATION_NAME My Application%

Some variables are set by the Hades interpreter.

Variable	Content
OS	The operating system, a script is being ran on (can be: NT, Mac, Linux, Other)
OS_VERSION	The version of the operating system as int (417, 1803, 10136, etc...)
HADES_VERSION	The version of the Hades interpreter the script is being ran on as int
HAS_EVAL	1 if the Hades runtime has the eval function, 0 if not
HAS_INTERNALS	1 if the Hades runtime has the std:internals library, 0 if not

if-else if-fi statement

The if-elif-fi block has a couple special commands to compare values to each other.

Command	Full name	Returns true if
eq	Equals	Variables are equal
ne	Not equals	Variables are not equal
gt	Greater than	First variable is greater than second variable
lt	Lower than	First variable is lower than second variable
ge	Greater or equals	First variable is greater or equal to second variable
le	Lower or equals	First variable is lower or equal to second variable

with os from std:os
with console from std:io

var listCommand

%if eq OS Windows%
listCommand = "dir"
%else if eq OS Linux%
listCommand = "ls"
%else%
console.out("OS not recognized!")
os.exit(-1)
&fi%

%if ge OS_VERSION 1803%
os.exec("wslpath 'c:\users'")
%fi%

os.exec(listCommand)

import statement

The import statement copies the content of the specified file and pastes it into the source code (works recursively).

function.hd

func print(args a)
    for(var arg in a)
        console.out(arg)
    end
end

classDef.hd

{% code title="" %}

class printer
%import function.hd%
end

{% endcode %}

main.hd

with console from std:io

%import classDef.hd%

printer().print("Hello","world")

Result

main.hd is being converted to:

with console from std:io

class printer
    func print(args a)
        for(var arg in a)
            console.out(arg)
        end
    end
end

printer().print("Hello","world")