Demonstrates that column information is not included with the line information for a function definition using the :on_module trace event.
Tested with Elixir 1.15.7 and OTP 26.1.1 on an apple silicon mac
This demo has some oddities with how the tracer is included (I'm not entirely sure how to include tracers inside your own application, so you should run mix clean before running mix compile.
mix clean
mix compileThis should emit the following output. You will observe that the metadata element of the tuple (the third element) only has a :line key, but the AST of the function itself has column information.
[lib/tracer_demo/tracer.ex:11: TracerDemo.Tracer.trace/2]
defs #=> [
some_macro: {:v1, :defmacrop, [line: 2],
[
{[line: 2], [{:list, [version: 0, line: 2, column: 24], nil}], [],
{:{}, [],
[
{:{}, [],
[
:.,
[column: 11],
[
{:{}, [], [:__aliases__, [column: 7, alias: false], [:Enum]]},
:map
]
]},
[column: 12],
[
{:list, [version: 0, line: 4, column: 24], nil},
{:{}, [],
[
:fn,
[column: 31],
[
{:{}, [],
[
:->,
[column: 38],
[
[{:{}, [], [:str, [column: 34], TracerDemo]}],
{:{}, [],
[
{:{}, [],
[
:.,
[column: 47],
[
{:{}, [], [:__aliases__, [column: 41, ...], [...]]},
:upcase
]
]},
[column: 48],
[{:{}, [], [:str, [column: 55], TracerDemo]}]
]}
]
]}
]
]}
]
]}}
]},
hello: {:v1, :def, [line: 8],
[
{[line: 8], [{:arg, [version: 0, line: 8, column: 13], nil}], [],
{:__block__, [],
[
{:<<>>, [alignment: 0, line: 9, column: 5],
[
{:"::", [inferred_bitstring_spec: true, line: 9, column: 5],
["hello ", {:binary, [line: 9, column: 5], nil}]},
{:"::", [line: 9, column: 12],
[
{{:., [line: 9], [String.Chars, :to_string]}, [line: 9],
[{:arg, [version: 0, line: 9, column: 14], nil}]},
{:binary, [], nil}
]},
{:"::", [inferred_bitstring_spec: true, line: 9, column: 5],
["!", {:binary, [line: 9, column: 5], nil}]}
]},
{{:., [line: 10, column: 11], [Enum, :map]}, [line: 10, column: 12],
[
["hello", {:arg, [version: 0, line: 10, column: 26], nil}, "!"],
{:fn, [line: 10, column: 31],
[
{:->, [line: 10, column: 38],
[
[
{:str,
[
version: 1,
line: 10,
counter: {TracerDemo, 4},
column: 34
], TracerDemo}
],
{{:., [line: 10, column: 47], [String, :upcase]},
[line: 10, column: 48],
[
{:str,
[
version: 1,
line: 10,
counter: {TracerDemo, 4},
column: 55
], TracerDemo}
]}
]}
]}
]}
]}}
]}
]