parser

Documentation

Overview

Package parser implements parsing and serializing an OpenGL ES Shading Language programs.

Index

• func FindBuiltin(name string) ast.Symbol
• func Formatter(e interface{}) fmt.Formatter
• func Parse(in string, language ast.Language, eval PreprocessorExpressionEvaluator) (program interface{}, version string, extensions []pp.Extension, err []error)
• type PreprocessorExpressionEvaluator

Functions

func FindBuiltin

func FindBuiltin(name string) ast.Symbol

FindBuiltin searches and returns the builtins for the symbol with the specified name. If no builtin has the specified name then nil is returned.

func Formatter

func Formatter(e interface{}) fmt.Formatter

Formatter is a helper function which turns any AST node into something that can be printed with %v. The returned object's default format will print the tree under the ast node in a reindented form. The alternate format flag (%#v) will print the node while preserving original whitespace, if this is present in the ***Cst nodes of the tree.

func Parse

func Parse(in string, language ast.Language, eval PreprocessorExpressionEvaluator) (program interface{}, version string, extensions []pp.Extension, err []error)

Parse is the main entry point into the parser. It parses GLES Shading Language programs and returns their AST representations. With suitable arguments it can also parse preprocessor #if expressions. It's arguments are:

- in: the string to parse. It is automatically preprocessed.

- language: which language are we parsing. In case we are parsing #if expressions (ast.LangPreprocessor), the eval function can be null.

- eval: An evaluator function which evaluates preprocessor #if expressions. It is only used when parsing full GLES Shading Language programs (ast.LangVertexShader, ast.LangFragmentShader).

The result is an object of type *ast.Ast in case of vertex and fragment shaders. In case of preprocessor expressions the result is an ast.Expression interface. The function also returns any errors it encounters during processing.

Types

type PreprocessorExpressionEvaluator

type PreprocessorExpressionEvaluator func(expr ast.Expression) (val ast.IntValue, err []error)

PreprocessorExpressionEvaluator is the type of the function arugment of the Parse function. These functions are supposed to evaluate preprocessor expressions, given an ast.Expression and return an IntValue and possibly a list of errors.