4. Match step sentences with cucumber expressions

Date: 2026-08-29

Status

Accepted

Context

A glue's sentence matcher was turned into a regex by two hand-rolled substitutions ({string}, {number}), and a step's arguments were the quoted literals found in the sentence, not what the matcher captured. {float} or {word} were impossible, 12.5 read as two arguments, and some sentences (a < b) could not be split at all.

Decision

Match step sentences with io.cucumber/cucumber-expressions, the reference implementation. A step's arguments are the captures of the expression, converted by their token. Keep {number} as an extra parameter type so existing glues still match. A #"..." glue stays a plain regex.

Generate the skeleton of a missing step with cucumber's CucumberExpressionGenerator.

Consequences

• All of cucumber's built-in types, optional text and alternation.
• /, ( and ) must be escaped in a string matcher.
• A regex glue passes its capture groups: a grouping-only group must be made non-capturing. On a real project, 9 glues out of 401 were concerned.
• The instaparse dependency is gone.