[PATCH cygport] Add 'vars' command to output arbitrary .cygport variables

[PATCH cygport] Add 'vars' command to output arbitrary .cygport variables

[Jon Turney]

Since variables in a .cygport file can be computed from arbitrary shell
expressions, perhaps containing variables that cygport itself defines,
other programs can't determine their value just by parsing the .cygport
file.

Add 'vars' command to output arbitrary variables defined by the .cygport
file.

The idea is that the output from this should be eval-able in a shell to
be further used, but it probably needs some additional escaping (of
newlines?) to be completely right in all cases.

e.g

> $ cygport libX11.cygport vars PVR BUILD_REQUIRES
> PVR='1.7.1-1'
> BUILD_REQUIRES='xtrans xorgproto libxcb-devel xmlto xorg-sgml-doctools docbook-xml43'

> eval $(cygport libX11.cygport vars BUILD_REQUIRES) ; for r in ${BUILD_REQUIRES} ; do echo $r; done
> xtrans
> xorgproto
> libxcb-devel
> xmlto
> xorg-sgml-doctools
> docbook-xml43
---

Notes:
    This is a generalization of the idea in [1], for querying the
    build-depends of a package.
    
    https://cygwin.com/pipermail/cygwin-apps/2021-January/041006.html

 bin/cygport.in               |  5 +++++
 data/cygport-bash-completion |  2 +-
 lib/pkg_info.cygpart         | 10 +++++++++-
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/bin/cygport.in b/bin/cygport.in
index afc6f7e..e9295be 100755
--- a/bin/cygport.in
+++ b/bin/cygport.in
@@ -623,6 +623,11 @@ do
 			__show_info;
 			_status=$?;
 			;;
+		vars)
+			__show_vars ${argv[@]:$((++arg_n))};
+			_status=$?;
+			arg_n=$argc;  # consumed all remaining args
+			;;
 		homepage|web*|www*)
 			__show_web;
 			_status=$?;
diff --git a/data/cygport-bash-completion b/data/cygport-bash-completion
index 86df238..9085e19 100644
--- a/data/cygport-bash-completion
+++ b/data/cygport-bash-completion
@@ -12,7 +12,7 @@ _cygport()
 		check test inst install list dep depends \
 		package pkg package-test pkg-test diff mkdiff mkpatch \
 		upload stage announce almostall all all-test clean finish \
-		help info version homepage website'
+		help info version homepage website vars'
 
 	if [[ $COMP_CWORD -eq 1 ]] ; then
 		# first arg: source file completion
diff --git a/lib/pkg_info.cygpart b/lib/pkg_info.cygpart
index 4b18993..a5475cc 100644
--- a/lib/pkg_info.cygpart
+++ b/lib/pkg_info.cygpart
@@ -658,5 +658,13 @@ __show_web() {
 	${mybrowser} ${mywww} &>/dev/null &
 }
 
+__show_vars() {
+	for v in "$@"
+	do
+		echo "${v}='${!v}'"
+	done
+}
+
 readonly -f __list_files __list_debug_files __list_deps \
-	    __show_deps __show_info __show_web __pager
+	    __show_deps __show_info __show_web __pager \
+	    __show_vars
-- 
2.31.1

Re: [PATCH cygport] Add 'vars' command to output arbitrary .cygport variables

[Brian Inglis]

On 2021-05-26 13:06, Jon Turney wrote:
> Since variables in a .cygport file can be computed from arbitrary shell
> expressions, perhaps containing variables that cygport itself defines,
> other programs can't determine their value just by parsing the .cygport
> file.
> 
> Add 'vars' command to output arbitrary variables defined by the .cygport
> file.
> 
> The idea is that the output from this should be eval-able in a shell to
> be further used, but it probably needs some additional escaping (of
> newlines?) to be completely right in all cases.
> 
> e.g
> 
>> $ cygport libX11.cygport vars PVR BUILD_REQUIRES
>> PVR='1.7.1-1'
>> BUILD_REQUIRES='xtrans xorgproto libxcb-devel xmlto xorg-sgml-doctools docbook-xml43'
> 
>> eval $(cygport libX11.cygport vars BUILD_REQUIRES) ; for r in ${BUILD_REQUIRES} ; do echo $r; done

bash "declare -p NAME..." seems to do what you want and produce .source-able output:

$ ( . mingw64-x86_64-nghttp2/mingw64-x86_64-nghttp2.cygport; declare -p BUILD_REQUIRES DESCRIPTION; echo echo 
\$BUILD_REQUIRES \$DESCRIPTION) | bash -svx
-bash: inherit: command not found
declare -- BUILD_REQUIRES="mingw64-x86_64-c-ares mingw64-x86_64-libevent mingw64-x86_64-win-iconv mingw64-x86_64-libxml2 
mingw64-x86_64-openssl mingw64-x86_64-zlib libev-devel mingw64-x86_64-binutils mingw64-x86_64-CUnit 
mingw64-x86_64-gcc-core mingw64-x86_64-gcc-g++ autoconf automake libtool pkg-config python3-sphinx"
+ declare -- 'BUILD_REQUIRES=mingw64-x86_64-c-ares mingw64-x86_64-libevent mingw64-x86_64-win-iconv 
mingw64-x86_64-libxml2 mingw64-x86_64-openssl mingw64-x86_64-zlib libev-devel mingw64-x86_64-binutils 
mingw64-x86_64-CUnit mingw64-x86_64-gcc-core mingw64-x86_64-gcc-g++ autoconf automake libtool pkg-config python3-sphinx'
declare -- DESCRIPTION="HTTP/2 and its header compression algorithm HPACK implementation.
The framing layer of HTTP/2 is implemented as a reusable library.
Also included are an HTTP/2 client, server, proxy, load test and
benchmarking tool, and Python modules.
Package provides Mingw MS VC RT-linked binaries, NOT Cygwin binaries,
for use with the mingw64-x86_64-gcc cross compiler, installed in
/usr/x86_64-w64-mingw32/sys-root/mingw/{bin,lib,include}/."
+ declare -- 'DESCRIPTION=HTTP/2 and its header compression algorithm HPACK implementation.
The framing layer of HTTP/2 is implemented as a reusable library.
Also included are an HTTP/2 client, server, proxy, load test and
benchmarking tool, and Python modules.
Package provides Mingw MS VC RT-linked binaries, NOT Cygwin binaries,
for use with the mingw64-x86_64-gcc cross compiler, installed in
/usr/x86_64-w64-mingw32/sys-root/mingw/{bin,lib,include}/.'
echo $BUILD_REQUIRES $DESCRIPTION
+ echo mingw64-x86_64-c-ares mingw64-x86_64-libevent mingw64-x86_64-win-iconv mingw64-x86_64-libxml2 
mingw64-x86_64-openssl mingw64-x86_64-zlib libev-devel mingw64-x86_64-binutils mingw64-x86_64-CUnit 
mingw64-x86_64-gcc-core mingw64-x86_64-gcc-g++ autoconf automake libtool pkg-config python3-sphinx HTTP/2 and its header 
compression algorithm HPACK implementation. The framing layer of HTTP/2 is implemented as a reusable library. Also 
included are an HTTP/2 client, server, proxy, load test and benchmarking tool, and Python modules. Package provides 
Mingw MS VC RT-linked binaries, NOT Cygwin binaries, for use with the mingw64-x86_64-gcc cross compiler, installed in 
'/usr/x86_64-w64-mingw32/sys-root/mingw/{bin,lib,include}/.'
mingw64-x86_64-c-ares mingw64-x86_64-libevent mingw64-x86_64-win-iconv mingw64-x86_64-libxml2 mingw64-x86_64-openssl 
mingw64-x86_64-zlib libev-devel mingw64-x86_64-binutils mingw64-x86_64-CUnit mingw64-x86_64-gcc-core 
mingw64-x86_64-gcc-g++ autoconf automake libtool pkg-config python3-sphinx HTTP/2 and its header compression algorithm 
HPACK implementation. The framing layer of HTTP/2 is implemented as a reusable library. Also included are an HTTP/2 
client, server, proxy, load test and benchmarking tool, and Python modules. Package provides Mingw MS VC RT-linked 
binaries, NOT Cygwin binaries, for use with the mingw64-x86_64-gcc cross compiler, installed in 
/usr/x86_64-w64-mingw32/sys-root/mingw/{bin,lib,include}/.

but eval dislikes the "declare --"!

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

This email may be disturbing to some readers as it contains
too much technical detail. Reader discretion is advised.
[Data in binary units and prefixes, physical quantities in SI.]

Re: [PATCH cygport] Add 'vars' command to output arbitrary .cygport variables

[Jon Turney]

On 28/05/2021 17:06, Brian Inglis wrote:
> On 2021-05-26 13:06, Jon Turney wrote:
>> Since variables in a .cygport file can be computed from arbitrary shell
>> expressions, perhaps containing variables that cygport itself defines,
>> other programs can't determine their value just by parsing the .cygport
>> file.
>>
>> Add 'vars' command to output arbitrary variables defined by the .cygport
>> file.
>>
>> The idea is that the output from this should be eval-able in a shell to
>> be further used, but it probably needs some additional escaping (of
>> newlines?) to be completely right in all cases.
>>
>> e.g
>>
>>> $ cygport libX11.cygport vars PVR BUILD_REQUIRES
>>> PVR='1.7.1-1'
>>> BUILD_REQUIRES='xtrans xorgproto libxcb-devel xmlto 
>>> xorg-sgml-doctools docbook-xml43'
>>
>>> eval $(cygport libX11.cygport vars BUILD_REQUIRES) ; for r in 
>>> ${BUILD_REQUIRES} ; do echo $r; done
> 
> bash "declare -p NAME..." seems to do what you want and produce 
> .source-able output:
> 
> $ ( . mingw64-x86_64-nghttp2/mingw64-x86_64-nghttp2.cygport; declare -p 
> BUILD_REQUIRES DESCRIPTION; echo echo \$BUILD_REQUIRES \$DESCRIPTION) | 
> bash -svx

Yeah, I should probably use 'declare -p'.

But just sourcing the .cygport is not adequate, as this can't determine 
variables which are generated by cygport itself (e.g. VR, 'inherit' for 
some cygclasses sets ARCH=noarch, etc.)

Re: [PATCH cygport] Add 'vars' command to output arbitrary .cygport variables

[Brian Inglis]

On 2021-05-31 10:14, Jon Turney wrote:
> On 28/05/2021 17:06, Brian Inglis wrote:
>> On 2021-05-26 13:06, Jon Turney wrote:
>>> Since variables in a .cygport file can be computed from arbitrary shell
>>> expressions, perhaps containing variables that cygport itself defines,
>>> other programs can't determine their value just by parsing the .cygport
>>> file.
>>> Add 'vars' command to output arbitrary variables defined by the .cygport
>>> file.
>>> The idea is that the output from this should be eval-able in a shell to
>>> be further used, but it probably needs some additional escaping (of
>>> newlines?) to be completely right in all cases.
>>> e.g

>>>> $ cygport libX11.cygport vars PVR BUILD_REQUIRES
>>>> PVR='1.7.1-1'
>>>> BUILD_REQUIRES='xtrans xorgproto libxcb-devel xmlto 
>>>> xorg-sgml-doctools docbook-xml43'
>>>> eval $(cygport libX11.cygport vars BUILD_REQUIRES) ; for r in 
>>>> ${BUILD_REQUIRES} ; do echo $r; done

>> bash "declare -p NAME..." seems to do what you want and produce 
>> .source-able output:
>> $ ( . mingw64-x86_64-nghttp2/mingw64-x86_64-nghttp2.cygport; declare 
>> -p BUILD_REQUIRES DESCRIPTION; echo echo \$BUILD_REQUIRES 
>> \$DESCRIPTION) | bash -svx

> Yeah, I should probably use 'declare -p'.
> But just sourcing the .cygport is not adequate, as this can't determine 
> variables which are generated by cygport itself (e.g. VR, 'inherit' for 
> some cygclasses sets ARCH=noarch, etc.)

I meant 'declare -p' solely as a means of getting properly escaped shell 
values (like other shell command -p option flags) out of cygport in 
statements which can be safely executed in other bash shell contexts.
The ./source was only a q&d means of setting the vars.

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

This email may be disturbing to some readers as it contains
too much technical detail. Reader discretion is advised.
[Data in binary units and prefixes, physical quantities in SI.]

[PATCH cygport] Add 'vars' command to output arbitrary .cygport variables

[Jon Turney]

Since variables in a .cygport file can be computed from arbitrary shell
expressions, perhaps containing variables that cygport itself defines,
other programs can't determine their value just by parsing the .cygport
file.

Add 'vars' command to output arbitrary variables defined by the .cygport
file.

The idea is that the output from this should be source-able in a shell
to be further used. e.g

> $ cygport libX11.cygport vars PVR BUILD_REQUIRES
> PVR='1.7.1-1'
> BUILD_REQUIRES='xtrans xorgproto libxcb-devel xmlto xorg-sgml-doctools docbook-xml43'

> $ source <(cygport libX11.cygport vars BUILD_REQUIRES) ; for r in ${BUILD_REQUIRES} ; do echo $r; done
> xtrans
> xorgproto
> libxcb-devel
> xmlto
> xorg-sgml-doctools
> docbook-xml43

v2: use 'declare -p'
---

Notes:
    This is a generalization of the idea in [1], for querying the
    build-depends of a package.
    
    https://cygwin.com/pipermail/cygwin-apps/2021-January/041006.html

 bin/cygport.in               |  5 +++++
 data/cygport-bash-completion |  2 +-
 lib/pkg_info.cygpart         | 10 +++++++++-
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/bin/cygport.in b/bin/cygport.in
index afc6f7e..e9295be 100755
--- a/bin/cygport.in
+++ b/bin/cygport.in
@@ -623,6 +623,11 @@ do
 			__show_info;
 			_status=$?;
 			;;
+		vars)
+			__show_vars ${argv[@]:$((++arg_n))};
+			_status=$?;
+			arg_n=$argc;  # consumed all remaining args
+			;;
 		homepage|web*|www*)
 			__show_web;
 			_status=$?;
diff --git a/data/cygport-bash-completion b/data/cygport-bash-completion
index 86df238..9085e19 100644
--- a/data/cygport-bash-completion
+++ b/data/cygport-bash-completion
@@ -12,7 +12,7 @@ _cygport()
 		check test inst install list dep depends \
 		package pkg package-test pkg-test diff mkdiff mkpatch \
 		upload stage announce almostall all all-test clean finish \
-		help info version homepage website'
+		help info version homepage website vars'
 
 	if [[ $COMP_CWORD -eq 1 ]] ; then
 		# first arg: source file completion
diff --git a/lib/pkg_info.cygpart b/lib/pkg_info.cygpart
index 4b18993..5d42ab4 100644
--- a/lib/pkg_info.cygpart
+++ b/lib/pkg_info.cygpart
@@ -658,5 +658,13 @@ __show_web() {
 	${mybrowser} ${mywww} &>/dev/null &
 }
 
+__show_vars() {
+	for v in "$@"
+	do
+		declare -p "${v}"
+	done
+}
+
 readonly -f __list_files __list_debug_files __list_deps \
-	    __show_deps __show_info __show_web __pager
+	    __show_deps __show_info __show_web __pager \
+	    __show_vars
-- 
2.31.1