Grader: output-matches

Taxonomy

Property	Value
Determinism	static
Cost	free
Reference	reference-free
Temporal scope	trajectory-level
Score kind	code

Config

graders:
  - type: output-matches
    config:
      pattern: "function\\s+\\w+\\("

Field	Type	Required	Description
pattern	string	Yes	Regular expression pattern to match against output
negate	boolean	No	When true, passes when the pattern does NOT match

Negated variant

Use output-not-matches as a shorthand for negate: true:

graders:
  - type: output-not-matches
    config:
      pattern: "(?i)error|exception"

This is equivalent to type: output-matches with negate: true.

Behavior

Constructs a RegExp from the pattern and tests it against trajectory.output. This is a regex search: the grader passes when the pattern matches anywhere in the output, so output with extra text before or after the match still passes. To require the entire output to match, anchor the pattern with ^ and $.

Inline flags: Use the (?flags) prefix syntax to set regex flags:

• (?i)pattern — case-insensitive matching
• (?m)pattern — multiline (^/$ match line start/end)
• (?s)pattern — dotAll (. matches newlines)
• (?ims)pattern — combine multiple flags

graders:
  - type: output-matches
    config:
      pattern: "(?i)function\\s+\\w+\\(" # case-insensitive

Passes when the pattern matches (or does NOT match if negated). Fails otherwise.

Evidence examples

✔ Output matches pattern /function\s+\w+\(/
✘ Output does not match pattern /function\s+\w+\(/