parse_transform
module for passage
Copyright © 2017 Takeru Ohta <phjgt308@gmail.com>
A parse_transform
module for passage
This module handles passage_trace
attribute.
If the attribute is appeared, the next function will be traced automatically.
See following example:
-module(example). -compile({parse_transform, passage_transform}). % Enables `passage_transform' -passage_trace([{tags, #{foo => bar}}, {eval_tags, #{size => "byte_size(Bin)"}}]). -spec foo(binary()) -> binary(). foo(Bin) -> <<"foo", Bin/binary>>.
The above foo
function will be transformed as follows:
foo(Bin) -> try passage_pd:start_span( 'example:foo/1', [{tags, #{application => example, module => example, line => 7, foo => bar}}]), passage_pd:set_tags(#{process => self(), size => byte_size(Bin)}), <<"foo", Bin/binary>> after passage_pd:finish_span() end.
expr_string() = string()
The textual representation of an expression.
When used, it will be converted to an AST representation as follows:
{ok, Tokens, _} = erl_scan:string(ExprString ++ "."), {ok, [Expr]} = erl_parse:parse_exprs(Tokens).
passage_trace_option() = {tracer, passage:tracer_id()} | {tags, passage:tags()} | {eval_tags, #{passage:tag_name() => expr_string()}} | {child_of, expr_string()} | {follows_from, expr_string()} | {error_if, expr_string()} | error_if_exception
passage:start_span/2
passage:start_span/2
tags
except the values are dynamically evaluated in the transforming phase.passage:start_span/2
passage:start_span/2
%% {error_if, ErrorPattern} case Body of ErrorPattern = Error -> passage_pd:log(#{message, Result}, [error]), Error; Ok -> Ok end.
try Body catch Class:Error -> passage_pd:log(#{'error.kind' => class, 'message' => Error, 'stack' => erlang:get_stacktrace()}, [error]), erlang:raise(Class, Error, erlang:get_stacktrace()) end.
parse_transform/2 | Performs transformations for passage |
parse_transform(AbstractForms, CompileOptions::list()) -> AbstractForms
Performs transformations for passage
Generated by EDoc, Oct 29 2017, 01:42:45.