* src/function.c: Introduce the 'let' built-in function
* tests/scripts/functions/let: Tests for the 'let' built-in function
---
This replaces:
> [PATCH 1/2] * src/function.c: Introduce the 'let' built-in function
and goes together with:
> [PATCH 2/2 V2] * doc/make.texi: Document the let function
On Fri, Oct 23, 2020 at 3:14 PM Paul Smith <psm...@gnu.org> wrote:
> Sorry for the delay. I have been super-busy (you'd think working from
> home would give one _more_ time but it seems not).
No problem. I am not in a hurry, but would love to see this land in the
next release.
> The thing most critically missing is a set of regression tests we can
> use to ensure that the feature is working (including various corner
> cases you would like to ensure), so that we can be sure it _keeps_
> working. Also I run these tests under valgrind and ASAN and similar to
> check for memory leaks and other errors.
The tests introduced here are mostly inspired by those of foreach.
Regards,
- Jouke
src/function.c | 53 +++++++++++++++++++++-
tests/scripts/functions/let | 89 +++++++++++++++++++++++++++++++++++++
2 files changed, 141 insertions(+), 1 deletion(-)
create mode 100644 tests/scripts/functions/let
diff --git a/src/function.c b/src/function.c
index 0917e0c..c4ff030 100644
--- a/src/function.c
+++ b/src/function.c
@@ -908,6 +908,55 @@ func_foreach (char *o, char **argv, const char *funcname
UNUSED)
return o;
}
+static char *
+func_let (char *o, char **argv, const char *funcname UNUSED)
+{
+ /* expand only the first two. */
+ char *varnames = expand_argument (argv[0], NULL);
+ char *list = expand_argument (argv[1], NULL);
+ const char *body = argv[2];
+
+ const char *vp;
+ const char *vp_next = varnames;
+ const char *list_iterator = list;
+ char *p;
+ size_t len;
+ size_t vlen;
+
+ push_new_variable_scope ();
+
+ /* loop through LIST for all but the last VARNAME */
+ vp = find_next_token (&vp_next, &vlen);
+ NEXT_TOKEN (vp_next);
+ while (*vp_next != '\0')
+ {
+ p = find_next_token (&list_iterator, &len);
+ if (*list_iterator != '\0')
+ {
+ ++list_iterator;
+ p[len] = '\0';
+ }
+ define_variable (vp, vlen, p ? p : "", o_automatic, 0);
+
+ vp = find_next_token (&vp_next, &vlen);
+ NEXT_TOKEN (vp_next);
+ }
+ /* set the last VARNAME to the remainder of LIST */
+ if (vp)
+ define_variable (vp, vlen, next_token (list_iterator), o_automatic, 0);
+
+ /* Expand the body in the context of the arguments, adding the result to
+ the variable buffer. */
+
+ o = variable_expand_string (o, body, SIZE_MAX);
+
+ pop_variable_scope ();
+ free (varnames);
+ free (list);
+
+ return o + strlen (o);
+}
+
struct a_word
{
struct a_word *next;
@@ -2337,7 +2386,8 @@ func_abspath (char *o, char **argv, const char *funcname
UNUSED)
comma-separated values are treated as arguments.
EXPAND_ARGS means that all arguments should be expanded before invocation.
- Functions that do namespace tricks (foreach) don't automatically expand. */
+ Functions that do namespace tricks (foreach, let) don't automatically
+ expand. */
static char *func_call (char *o, char **argv, const char *funcname);
@@ -2373,6 +2423,7 @@ static struct function_table_entry function_table_init[] =
FT_ENTRY ("words", 0, 1, 1, func_words),
FT_ENTRY ("origin", 0, 1, 1, func_origin),
FT_ENTRY ("foreach", 3, 3, 0, func_foreach),
+ FT_ENTRY ("let", 3, 3, 0, func_let),
FT_ENTRY ("call", 1, 0, 1, func_call),
FT_ENTRY ("info", 0, 1, 1, func_error),
FT_ENTRY ("error", 0, 1, 1, func_error),
diff --git a/tests/scripts/functions/let b/tests/scripts/functions/let
new file mode 100644
index 0000000..d3dbe1a
--- /dev/null
+++ b/tests/scripts/functions/let
@@ -0,0 +1,89 @@
+# -*-perl-*-
+# $Id$
+
+$description = "Test the let function.";
+
+$details = "This is a test of the let function in gnu make.
+This function destructures a list of values and binds each
+value to a variable name in a list of variable names.
+Superfluous variable names are assigned the empty string and
+the remaining values are assigned to the last variable name.
+The binding holds for the duration of the evaluation of the
+given text and no longer. The general form of the command
+is $(let \$vars,\$list,\$text). Several types of let
+assignments are tested\n";
+
+
+# Allow empty variable names and empty value list.
+# We still expand the list and body.
+run_make_test('
+null =
+x = $(let $(null),$(info side-effect),abc)
+y = $(let y,,$ydef)
+
+all: ; @echo $x$y',
+ '', "side-effect\nabcdef\n");
+
+# The example macro from the manual.
+run_make_test('
+reverse = $(let first rest,$1,$(if $(rest),$(call reverse,$(rest)) )$(first))
+
+all: ; @echo $(call reverse, \
+ moe miny meeny eeny \
+ )',
+ '', "eeny meeny miny moe\n");
+
+
+# Set an environment variable that we can test in the makefile.
+$ENV{FOOFOO} = 'foo foo';
+
+# Verify masking: expansion outside the scope of let is unaffected.
+run_make_test('
+auto_var = \
+ udef \
+ CC \
+ FOOFOO \
+ MAKE \
+ foo \
+ CFLAGS \
+ WHITE \
+ @ \
+ <
+av = $(foreach var, $(auto_var), $(origin $(var)) )
+foo = bletch null @ garf
+override WHITE := BLACK
+
+define mktarget
+target: foo := $(foo)
+target: ; @echo $(AR)_$(foo)_
+endef
+
+all: auto target
+auto: ; @echo $(let $(auto_var),,$(av)) $(av)
+$(let AR foo,bar foo ,$(eval $(value mktarget)))',
+ '-e WHITE=WHITE CFLAGS=',
+ "automatic automatic automatic automatic automatic automatic
automatic automatic automatic undefined default environment default file
command line override automatic automatic
+ar_foo _
+");
+
+
+# Check some error conditions.
+run_make_test('
+x = $(let )
+y = $x
+
+all: ; @echo $y',
+ '',
+ "#MAKEFILE#:2: *** insufficient number of arguments (1) to
function 'let'. Stop.",
+ 512);
+
+run_make_test('
+x = $(let x,y)
+y := $x
+
+all: ; @echo $y',
+ '',
+ "#MAKEFILE#:2: *** insufficient number of arguments (2) to
function 'let'. Stop.",
+ 512);
+
+1;
--
2.29.2
