utils

ParamToken §

Bases: enum.Enum

Parameters in a path are inside curly braces and may include a colon and a regex.

This enum represents the only characters our parser will look for to extract the elements of the Dynamic node.

first_nonequal_idx(left, right)

Find first string index where left and right strings do not match

In [1]: first_nonequal_idx("", "californian")
Out[1]: 0

In [2]: first_nonequal_idx("aba", "abc")
Out[2]: 2

Note, if the strings match, the first-non-equal index will be equal to the length of the string:

In [3]: first_nonequal_idx("aba", "aba")
Out[3]: 3

parse_dynamic(path)

This method discerns the dynamic elements in a string.

There are some assumptions involved

This will be used in URI paths, so regexes will be for typically allowed URI characters
A dynamic element always begins with the char { and ends with the char }
A colon separates a parameter name from a regex, which are optional.
It is possible to include nested braces as part of a regex, but they must be matched:
This is fine: {name:[a-zA-Z]{10}}
This (a valid regex) will raise an exception: {code:[}{}]}
We may later construct a named pattern out of this, so any parenthesis in the pattern will likely break.

Returns a generator that yields in turn, static strings and DynamicParseNodes:

test = "/company/{name:[a-z][A-Z]{10}[0-9]*}/bla/bla/{dept}" list(parse_dynamic(test)) ['/company/', , '/bla/bla/', ]