builder-js v0.0.1-dev

• Syntax
  • Directives
    • @set
    • @macro
    • @if – elseif – @else
    • @{...} (inline expressions)
    • @error
    • @include
      • Macro
      • Local Files
      • Remote Files
      • From Git Repository
  • Expressions
    • Types
    • Operators
      • Binary
      • Unary
    • Member Expressions
    • Conditional Expressions
    • Variables
      • __LINE__
      • __FILE__
    • Functions
  • Comments
• License

Builder language combines a preprocessor with an expression language and advanced imports.

Please note that the works is in-progress and published for preview purposes only.

Syntax

Directives

Directives start with @ symbol.

@set

Assigns a value of an expression to a variable.

Variables are defined in a global context.

Example:

Sets SOMEVAR to 1:

@macro

@endmacro can be replaced with @end.

Declares a block of code that can take parameters and can be used with an @include statement. Once declared, macros are available from anywhere.

Variables declared as macro argumentys are only available within the macro scope and override global variables with the same name (but do not change them).

Example:

Then some_macro can be used as:

which will produce:

Hello, username!
Roses are red,
And violets are of undefiend color.

@if – @elseif – @else

Conditional directive.

@endif can be replaced with @end.

Example:

@{...} (inline expressions)

Inserts the value of the enclosed expression.

Example:

results in the following output:

Hello, Someone, the result is: 56088.

@error

Emits an error.

Example:

@include

Includes local file, external source or a macro.

Macro

Local Files

Remote Files

From Git Repository

For example, importing file from GitHub looks like:

• Head of the default branch

• Head of the master branch

• Tag v1.2.3:

• Latest available tag

Expressions

Directives that have parameters allow usage of expression syntax.

For example:

• @include <source:expression>
• @set <variable:identifier> <value:expression>
• @if <condition:expression>
• @elseif <condition:expression>
• @{<expression>} (inline expressions)

Types

The following types are supported in expressions:

• numbers (eg: 1,1E6, 1e-6, 1.567)
• strings (eg: "abc", 'abc')
• null
• true
• false

Operators

Binary

|| && == != < > <= >= + - * / %

Unary

+ - !

Member Expressions

• somevar.member
• somevar["member"]
• ([1, 2, 3])[1]

Conditional Expressions

test ? consequent : alternate

Variables

• Variables defined by <b>@set</b> statements are available in expressions.
• Undefined variables are evaluated as null.
• Variable names can contain $, _, latin letters and digits and can start only with a non-digit.

__LINE__

Line number (relative to the file in which this variable appears).

Example:

__FILE__

Name of the file in which this variable appears.

Example:

Functions

• min(<numbers>)
• max(<numbers>)
• abs(<number>)
• defined(<variable_name>) – returns true if a variable is defined, false otherwise.

Comments

Lines starting with @ followed by space or a line break are treated as comments and not added to the output.

Example:

License

MIT

Author

Mikhail Yurasov mikhail@electricimp.com