coen.bakker
Getting `unexpected reserved word: end` when returning string from function
When I define successive functions that return a string I get the error:
unexpected reserved word: end
HINT: it looks like the "end" on line 3 does not have a matching "do" defined before it
(elixir 1.14.0) lib/kernel/parallel_compiler.ex:346: anonymous fn/5 in Kernel.ParallelCompiler.spawn_workers/7
The error refers to line 3 of this function:
defmodule ModuleA do
@start "@"
@end "#"
defmacro start, do: @start
defmacro end, do: @end
end
However, the error also occurs in a simpler setup, like:
defmodule ModuleB do
def start, do: "@"
def end, do: "#"
end
The error does not occur in a module with only one function that returns a string.
defmodule ModuleC do
def start, do: "@"
end
I reckon it something small I am overlooking, but it bugs me that I don’t understand why it fails. Any ideas?
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patrickdm
Because end is a reserved word?
from: Syntax reference — Elixir v1.12.3
Reserved words
These are the reserved words in the Elixir language. They are detailed throughout this guide but summed up here for convenience:true, false, nil - used as atoms
when, and, or, not, in - used as operators
fn - used for anonymous function definitions
do, end, catch, rescue, after, else - used in do/end blocks
Interactive Elixir (1.14.2) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> defmodule ModuleB do
...(1)> def start, do: "@"
...(1)> def end, do: "f"
** (SyntaxError) iex:3:8: syntax error before: ','
|
3 | def end, do: "f"
| ^
(iex 1.14.2) lib/iex/evaluator.ex:292: IEx.Evaluator.parse_eval_inspect/3
(iex 1.14.2) lib/iex/evaluator.ex:187: IEx.Evaluator.loop/1
(iex 1.14.2) lib/iex/evaluator.ex:32: IEx.Evaluator.init/4
(stdlib 4.0.1) proc_lib.erl:240: :proc_lib.init_p_do_apply/3
benwilson512
Yeah as @patrickdm notes end is reserved, I would pick a different function / macro name. Even if you can successfully construct a function / macro named end it’s going to be very difficult to call.
coen.bakker
Oh boy. I knew that. Must be tired. 
Makes all sense now. Thank you!
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