Parser

The Parser processes the Token stream from the lexer and produces a Template class.

class knights.parser.Parser(source, loader)

Used to parse token streams and produce a template class.

loader

The loader.TemplateLoader instance for this parser to use, or None. This value is passed via the compiler.kompile call from the loader.TempateLoader, and is required for the {% extends %} and {% include %} tags to work.

stream

A lexer.tokenise generator.

parent = None

The parent class to use for this Template

methods

A list of ast.Method nodes

tags

Tag generators loaded from tag libraries.

helpers

Helper functions loaded from tag libraries.

load_library(path)

Load a custom tag library from path.

It is assumed it will contain an object called register, which will have dict properties tags and helpers to be updated with the parsers.

build_method(name, endnodes=None)

Build a new method called name, and make its body the set of nodes up to any listed in endnodes, or the end if None.

The method is appended to self.methods

parse_node(endnodes=None)

Yield a stream of AST Nodes based on self.stream

text nodes will produce effectively:

yield token

var nodes will produce code to evaluate the expression and yield their value.

block nodes will be resolved through the registered tags, unless they match any listed in endnodes, in which case the raw name will be yielded before terminating the loop.

parse_nodes_until(*endnodes)

Return two values - a list of nodes, and the name of the matching end node. This is used for implementing

build_class()

Construct a Class definition from the current state.

The base class will either be ‘object’ if self.parent is None, else ‘parent’.

parse_expression(expr)

Helper method to parse an expression and convert raw variable references to context lookups.

parse_args(expr)

Helper method to parse an expression and yield a list of args and kwargs.

knights.parser.wrap_name_in_context(name)

Utility function to turn an ast.Name() node into code to affect:

context['name']

class knights.parser.VarVisitor

A subclass of :ast:NodeTransformer which applies wrap_name_in_context to all Name nodes in the AST it visits.