no-lines: avoid leaving an empty line instead of the syncline

Currently, with --no-lines, instead of "#line file line\n", we emit
"\n".  Let's emit nothing.

* data/skeletons/bison.m4 (b4_syncline): Emit at end-of-line when enabled.
* data/skeletons/bison.m4, data/skeletons/c.m4, data/skeletons/glr.cc,
* data/skeletons/lalr1.cc, src/output.c: Use dnl after b4_syncline to
avoid spurious empty lines.

* tests/synclines.at (Sync Lines): Make sure that --no-lines is like
grep -v #line.
* tests/calc.at: Make sure that a rich grammar file behaves properly
with %no-lines.

2 files changed, 34 insertions, 3 deletions

diff --git a/tests/calc.at b/tests/calc.at
index b2584576..99f1160c 100644
--- a/tests/calc.at
+++ b/tests/calc.at
@@ -714,6 +714,7 @@ AT_CHECK_CALC_LALR([%define api.push-pull both %define api.pure full %define par
 
 AT_CHECK_CALC_LALR([%define api.pure %define parse.error verbose %debug %locations %defines %define api.prefix {calc} %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
 
+AT_CHECK_CALC_LALR([%no-lines %define api.pure %define parse.error verbose %debug %locations %defines %define api.prefix {calc} %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
 
 # ----------------------- #
 # Simple GLR Calculator.  #
@@ -753,6 +754,8 @@ AT_CHECK_CALC_GLR([%define api.pure %define parse.error verbose %debug %location
 AT_CHECK_CALC_GLR([%define api.pure %define parse.error verbose %debug %locations %defines %name-prefix "calc" %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
 AT_CHECK_CALC_GLR([%define api.pure %define parse.error verbose %debug %locations %defines %define api.prefix {calc} %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
 
+AT_CHECK_CALC_GLR([%no-lines %define api.pure %define parse.error verbose %debug %locations %defines %define api.prefix {calc} %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
+
 
 # ----------------------------- #
 # Simple LALR1 C++ Calculator.  #
@@ -790,6 +793,8 @@ AT_CHECK_CALC_LALR1_CC([%defines %locations %define parse.error verbose %debug %
 AT_CHECK_CALC_LALR1_CC([%defines %locations %define api.location.file none])
 AT_CHECK_CALC_LALR1_CC([%defines %locations %define api.location.file "my-location.hh"])
 
+AT_CHECK_CALC_LALR1_CC([%no-lines %defines %locations %define api.location.file "my-location.hh"])
+
 
 # --------------------------- #
 # Simple GLR C++ Calculator.  #
@@ -821,6 +826,7 @@ AT_CHECK_CALC_GLR_CC([%define parse.error verbose %debug %name-prefix "calc" %de
 AT_CHECK_CALC_GLR_CC([%locations %defines %define parse.error verbose %debug %name-prefix "calc" %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
 AT_CHECK_CALC_GLR_CC([%locations %defines %define parse.error verbose %debug %define api.prefix {calc} %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
 
+AT_CHECK_CALC_GLR_CC([%no-lines %locations %defines %define parse.error verbose %debug %define api.prefix {calc} %verbose %yacc %parse-param {semantic_value *result} %parse-param {int *count}])
 
 
 # --------------------------- #
diff --git a/tests/synclines.at b/tests/synclines.at
index 857a6ca5..2a8a5fd8 100644
--- a/tests/synclines.at
+++ b/tests/synclines.at
@@ -28,7 +28,7 @@ AT_BANNER([[Sync Lines.]])
 m4_define([_AT_SYNCLINES_COMPILE],
 [AT_CHECK([$CC $CFLAGS $CPPFLAGS -c $1], [ignore], [], [stderr])
 
-# Transform stderr into something like this:
+# Transform the file 'stderr' into something like this:
 #
 #   input.y:4: #error "4"
 #
@@ -121,7 +121,7 @@ EOF
 
 # AT_SYNCLINES_COMPILE(FILE)
 # --------------------------
-# Compile FILE expecting an error, and save in the file stdout the
+# Compile FILE expecting an error, and save in the file 'stdout' the
 # normalized output.  If we can't get a trustable location
 # from the compiler, just skip the test.
 #
@@ -449,11 +449,36 @@ AT_DATA_GRAMMAR([input.y],
 ]AT_YYERROR_DECLARE_EXTERN[
 ]AT_YYLEX_DECLARE_EXTERN[
 %}
+%union {
+  int ival;
+}
 %%
 exp: '0'
 ]])
+
+# Generate without.* without the #line.  Don't use -o without.c which
+# would change the content (e.g., CPP guard depend on the output file
+# name).
 AT_BISON_CHECK([--no-lines -o input.AT_LANG_EXT -d input.y])
-AT_CHECK([[grep '#line'] *.AT_LANG_EXT *.AT_LANG_HDR], 1)
+AT_CHECK([mv input.]AT_LANG_EXT[ without.]AT_LANG_EXT[])
+AT_CHECK([mv input.]AT_LANG_HDR[ without.]AT_LANG_HDR[])
+# There is no #line at all.
+AT_CHECK([grep '#line' *.]AT_LANG_EXT[ *.]AT_LANG_HDR[], 1)
+
+# Generate with.* without the #line.
+AT_BISON_CHECK([-o input.AT_LANG_EXT -d input.y])
+AT_CHECK([mv input.]AT_LANG_EXT[ with.]AT_LANG_EXT[])
+AT_CHECK([mv input.]AT_LANG_HDR[ with.]AT_LANG_HDR[])
+
+# The implementation file with --no-line is exactly the
+# original one with #lines removed.
+AT_CHECK([grep -v '#line' with.]AT_LANG_EXT[ >expout])
+AT_CHECK([cat without.AT_LANG_EXT], 0, [expout])
+
+# Likewise for the header.
+AT_CHECK([grep -v '#line' with.]AT_LANG_HDR[ >expout])
+AT_CHECK([cat without.AT_LANG_HDR], 0, [expout])
+
 AT_BISON_OPTION_POPDEFS
 
 AT_CLEANUP