directive

0.1.0 • Public • Published

directive

Patrick Mueller
pmuellr@gmail.com

Summary

directive is a code parsing system based on the recognition that most programs tend to be structured as a set of blocks of the form:

  • comment
  • definition
  • body

For example:

/** 
 * this is a comment
 */
myFunction(arg1, arg2)
{
   for (something) { somethingElse() }
}

In that example, you have a comment, followed by the definition of the myFunction procedure, followed by the body of the procedure.

With directive, you use a standard format to write your comments, definitions, and bodies. Definitions are actually called directives.

Parsing Rules

The parsing rules are line based, so things like multi-line comments and multi-line expressions are not directly handled by the system.

The basic rules for the different parts of a directive are:

  • comment

    A comment block begins with a line that contains a / or # character in column one. It continues until a directive.

  • directive

    A directive is a single line which begins with an alphabetic character, $ or @.

  • body

    A body block begins after a directive, and continues to a comment or directive. Every line of a body (except empty lines) must begin with at least one white-space character.

API

To use directive, you must first create a DirectiveReader with the constructor

DirectiveReader(source, fileName, lineNumber)

source is the source file containing the directives, fileName is the name of the file, and lineNumber is the line the source starts at (for embedded directives in other files).

With the resulting DirectiveReader object, you can invoke the method

directiveReader.process(handler)

handler is an object containing functions that are called back at various times during the processing. Methods which must be implemented in this object include:

  • processDirective(event)

  • fileBegin(event)

  • fileEnd(event)

See the examples for the actual data passed in the events.

In addition, you can provide functions of the form:

handleDirective_[directiveName]

where [directiveName] is a specific directive that you want to handle. Rather than invoking the processDirective method for this directive, the specified handleDirective_[directiveName] method will be invoked instead.

Examples

See the test cases for examples. In particular, the files in the test/test-files directory contain sample inputs with the list of events that are generated for that input, so you can see exactly what gets generated.

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Install

npm i directive

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Version

0.1.0

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Collaborators

  • pmuellr