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bug#22142: A bug with define-syntax

From: Mark H Weaver
Subject: bug#22142: A bug with define-syntax
Date: Tue, 15 Dec 2015 03:19:43 -0500
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux)

Tommi Höynälänmaa <address@hidden> writes:

> I get the following error message:


> ERROR: In procedure #<syntax-transformer assert>:
> ERROR: Wrong type to apply: #<syntax-transformer assert>
> make: *** [hello-world.scm] Virhe 1
> --- cut here ---
> The code should compile.

This error indicates, roughly speaking, that 'assert' was used before it
was defined.  More precisely: an expression that uses the 'assert' macro
was (macro-)expanded before 'assert' was defined.

This works in Guile 1.x, because it's a pure interpreter that performs
macro expansion lazily, i.e. it delays expansion of a given expression
until the first time the expression is evaluated.  This allows you to
_define_ a procedure that uses 'assert' before 'assert' is defined, as
long as the procedure is not _applied_ (i.e. called) before 'assert' is

Guile 2.x uses a new macro expander that is far superior in most
respects, but it does not support lazy expansion, and therefore strictly
requires that macros be defined before their uses are expanded.


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