RegEx/REST/Variable.regex.txt

# Matches URL segments and query strings containing variables.
# Variables can be enclosed in brackets or curly braces, or preceeded by a $ or :
(?> # A variable can be in a URL segment or subdomain
    (?<Start>[/\.]) # Match the <Start>ing slash|dot ...
    (?<IsOptional>\?)? # ... an optional ? (to indicate optional) ...
    (?:
        \{(?<Variable>\w+)\}| # ... A <Variable> name in {} OR
        \[(?<Variable>\w+)\]| # A <Variable> name in [] OR
        \<(?<Variable>\w+)\>| # A <Variable> name in <> OR
        `\$(?<Variable>\w+) | # A `$ followed by a <Variable> OR
        \:(?<Variable>\w+) # A : followed by a <Variable>
    )
|
    (?<IsOptional> # If it's optional it can also be
        [{\[](?<Start>/) # a bracket or brace, followed by a slash
    )
    (?<Variable>\w+)[}\]] # then a <Variable> name followed by } or ]
| # OR it can be in a query parameter:
    (?<Start>[\?\&]) # Match The <Start>ing ? or & ...
    (?<Query>[\$\w\-]+) # ... the <Query> parameter name ...
    = # ... an equals ...
    (?<IsOptional>\?)? # ... an optional ? (to indicate optional) ...
    (?:
        \{(?<Variable>\w+)\}| # ... A <Variable> name in {} OR
        \[(?<Variable>\w+)\]| # A <Variable> name in [] OR
        \<(?<Variable>\w+)\>| # A <Variable> name in <> OR
        `\$(?<Variable>\w+) | # A $ followed by a <Variable> OR
        \:(?<Variable>\w+) # A : followed by a <Variable>
    )
)