
[;1m  match_spec_test(MatchAgainst, MatchSpec, Type)[0m

[;;4mSince[0m:
  OTP 19.0

  Tests a match specification used in calls to [;;4mets:select/2[0m and [;;4m[0m
  [;;4mtrace:function/4[0m.

  The function tests both a match specification for "syntactic"
  correctness and runs the match specification against the object.
  If the match specification contains errors, the tuple [;;4m{error,[0m
  [;;4mErrors}[0m is returned, where [;;4mErrors[0m is a list of natural language
  descriptions of what was wrong with the match specification.

  If [;;4mType[0m is [;;4mtable[0m, the object to match against is to be a
  tuple. The function then returns [;;4m{ok,Result,[],Warnings}[0m, where [;;4m[0m
  [;;4mResult[0m is what would have been the result in a real [;;4mets:select/2[0m
  call, or [;;4mfalse[0m if the match specification does not match the
  object tuple.

  If [;;4mType[0m is [;;4mtrace[0m, the object to match against is to be a list.
  The function returns [;;4m{ok, Result, Flags, Warnings}[0m, where [;;4m[0m
  [;;4mResult[0m is one of the following:

   • [;;4mtrue[0m if a trace message is to be emitted

   • [;;4mfalse[0m if a trace message is not to be emitted

   • The message term to be appended to the trace message

  [;;4mFlags[0m is a list containing all the trace flags to be enabled,
  currently this is only [;;4mreturn_trace[0m.

  This is a useful debugging and test tool, especially when writing
  complicated match specifications.

  See also [;;4mets:test_ms/2[0m.
