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Wrap value which has opaque Show instance.

Generates consequent pattern variable for tracing arguments of a guarded function. It is assumed that a is used together with tg and u.

foo $a $a $a | $tg = $u
foo 0  _  _ = 0
foo x y z = x + y + z

Similar to a, but argument is not included in trace message.

Expands to $(tr "/a b c d...") False

Similar to tg with message prefix with the argument.

TH version of trace and traceEvent The message is formatted according to TraceMessageFormat. The generated expression has type forall r (a :: TYPE r) b a. Rewrap a b => a -> a. id is generated if effective trace level is lower than trace level threshold. Example:

foo x = $(tr "get/x") x

Output:

Module::foo get; x : 132

TH version of traceMarker where module and function are used as a marker. Trace level is used.

TH version of traceIO and traceEventIO The message is formatted according to TraceMessageFormat. Example:

foo x = $(trIo "get/x") >> pure x

Output:

Module::foo get; x : 132

TH version of traceMarkerIO where module and function are used as a marker. Trace level is not used.

TH version of traceWith and traceEventWith The message is formatted according to TraceMessageFormat. The generated expression has type forall r (a :: TYPE r) b a. (Show a, Rewrap a b) => a -> a. id is generated if effective trace level is lower than trace level threshold. Example:

foo x = $(tw "get/x") (x + 1)

Output:

Module::foo get; x : 132 => 133

Like tw but return value is wrapped with ShowTrace.

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