JavaScript Script Blocks

Script Blocks provide and easy, and inline way to use JavaScript to generate, or insert values into, your commands.

Inline Scripts

Used to evaluate some JavaScript and inline the result into a command.

<%...%>

Scope

Variables, and functions that are available for use in inline script blocks.

• context

  The current Compiler Context.

• embed(block: BoundBlock)

  Takes a BoundBlock instance and embeds a reference to it.

• Global Scope

Argument Scope

Argument scope is the special scope that is used when an Inline Scripts is used as an argument for MC-Build Compile-time features, such as REPEAT, or IF expressions.

It has access to everything the normal inline script scope has, except for the embed function.

Examples

Using an Inline Script

Code

say <% 1 + 1 %> <%10*10%>

REPEAT (1, 10) as i {
    say <% i %>
}

Output

say 2 100
say 1
say 2
say 3
say 4
say 5
say 6
say 7
say 8
say 9
say 10

Multi-line Scripts

Used to evaluate more complex JavaScript. Instead of injecting the return result of the script into a command, Multi-line Scripts include a few functions that can be used to generate commands, and more.

<%%
    ...
%%>

Scope

Variables, and functions that are available for use in multi-line script blocks.

• emit(str: String)

  Emits a string into the output.

• emit.mcb(str: String)

  Emits a string into the output after running it through the MC-Build compiler.

• emit.block(commands: Array[String])

  Takes a list of commands, generates a function, and emits a call to that function.

• context

  The current Compiler Context.

• embed(block: BoundBlock)

  Takes a BoundBlock instance and embeds a reference to it.

• require(path: String)

  Requires a file relative to the current file. Same as the require function in Node.js.

• Global Scope

Examples

Using a Multi-line Script

Code

function say_hello {
    <%%
        emit("say Hello World")
        for (let i = 0; i < 3; i++) {
            emit(`say ${i}`)
        }
    %%>
}

say_hello.mcfunction

say Hello World
say 0
say 1
say 2

Generating Functions with Multi-line Scripts

Code

<%%
    for (let i = 0; i < 3; i++) {
        emit.mcb(`function say_${i} {
            say ${i}
        }`)
    }
%%>

say_0.mcfunction

say 0

say_1.mcfunction

say 1

say_2.mcfunction

say 2

Global Scope

Variables, and functions that are available for use in all script blocks.

• REPEAT

  the method that produces an iterator used for evaluating REPEAT expressions.

• store

  An object that can be used to store misc values that persist between script blocks, but not between builds.

• global

  An object that can be used to store misc values that persist between script blocks, and persist between builds.

• config

  An object that contains the user-defined values from the config.json file.