param-parser

param-parser is a parser library for a param string expression. Those expressions are arbitrary strings with placeholders in it, where a placeholder consists of a name, an optional type and a list of options.

Installation

With a correctly configured pipenv toolchain:

pipenv install param-parser

You may also use classic pip to install the package:

pip install param-parser

Getting started

Examples of param string expressions look as follows:

this-is-a-{param:string:option1,option2,option3}-expression
this-is-a-{param:string}-expression
this-is-a-{param}-expression

As you see, a param is introduced by an opening curly bracket, followed by the name of the param, a colon, the type of the param, another colon and a comma separated list of options. The param configuration gets terminated by a closing curly bracket. Note that the type and option configuration are optional, but the name is mandatory.

To parse an expression shown above, use the Python code as follows:

import param_parser

result = param_parser.parse(r"this-is-a-{param:string:option1,option2,option3}-expression")

result[0]  # Gets a `param_parser.node.SequenceNode` instance
result[0].sequence_value  # Gets `"this-is-a-"` as a string

result[1]  # Gets a `param_parser.node.ParamNode` instance
result[1].param_name  # Gets `"param"` as a string
result[1].param_type  # Gets `"string"` as a string
result[1].param_options  # Gets `["option1", "option2", "option3"]` as a list of strings

result[2]  # Gets a `param_parser.node.SequenceNode` instance
result[2].sequence_value  # Gets `"-expression"` as a string

It is also possible to escape opening curly brackets, closing curly brackets, colons and commas as follows:

import param_parser

result = param_parser.parse(r"this-is-a-\{param:string:option1,option2,option3\}-expression")

result[0]  # Gets a `param_parser.node.SequenceNode` instance
result[0].sequence_value  # Gets `"this-is-a-{param:string:option1,option2,option3}-expression"` as a string

Supported versions

List of developers

• Andreas Stocker AStocker@anexia-it.com, Lead Developer