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feat(config): static interpolating variables (variables {})
A new optional variables {} config section defines NAME = value pairs that menu/form authors reference as $NAME / ${NAME} to cut duplication. Values may reference each other; cross-references are resolved once at config load (a few fixpoint passes; undefined names left verbatim). In menu/form actions and field list_cmd commands, expand_vars() substitutes the defined names before the command runs (at the choke points exec_command / call_system / run_browse / the final exec); any other $... (e.g. $HOME) is left for the shell. CCFE-side substitution, not env export -- so a value may contain shell metacharacters and nothing clobbers PATH/HOME. The variables are as trusted as the menus/forms; under restricted mode config is system-locked and the allow-list still checks the command as written (a bare $VAR program name is refused unless allow-listed). Documented in ccfe.conf(5). Demo for testing: ccfe.conf ships a variables {} block (DEMO_NAME, DEMO_HELLO referencing it, LIST_DIR=/etc) and a new demo menu entry "Config variables demo" (demo.d/vars.form) whose list_cmd lists $LIST_DIR and whose action greets via $DEMO_HELLO. Covered by t/34 (cross-ref in a run: action, $HOME shell pass-through, a variable in a list_cmd). Full suite green (378); ccfe.pl tidy+critic gates pass. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Lines changed: 239 additions & 4 deletions

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‎src/ccfe.conf‎

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Original file line numberDiff line numberDiff line change
@@ -73,3 +73,14 @@ active_field_attr {
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changed_value_fg = A_NORMAL
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changed_value_bg = A_REVERSE
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}
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# User-defined variables (see ccfe.conf(5) "VARIABLES CONFIGURATION SECTION").
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# Define a value once and reference it as $NAME / ${NAME} in menu and form
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# actions and in a field's list_cmd. Variables may reference each other; the
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# references are resolved when the configuration is loaded. Used by the
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# "Config variables demo" form (demo.d/vars.form).
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variables {
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DEMO_NAME = CCFE
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DEMO_HELLO = Hello from ${DEMO_NAME} configuration variables!
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LIST_DIR = /etc
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}

‎src/ccfe.pl‎

Lines changed: 70 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -820,8 +820,25 @@ sub load_msgs {
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close(INF);
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}
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823+
# Substitute $NAME / ${NAME} references to config `variables {}` in a command or
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# action string with their resolved values. Only names defined in the section
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# are replaced; any other $... is left untouched for the shell. The variables
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# are system-config-owned (and config-locked under RESTRICTED), so this is a DRY
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# convenience for menu/form authors, not an untrusted-input path. Applied at
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# the command choke points (exec_command / call_system / run_browse / the final
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# exec). (FEATURE-REQUESTS item 3.)
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sub expand_vars {
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my ($str) = @_;
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return $str unless defined $str;
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my $vars = $ctx->{cfg}{vars} or return $str;
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$str =~ s/\$\{(\w+)\}/ exists $vars->{$1} ? $vars->{$1} : "\${$1}" /ge;
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$str =~ s/\$(\w+)/ exists $vars->{$1} ? $vars->{$1} : "\$$1" /ge;
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return $str;
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}
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sub exec_command {
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my ( $cmd, $extra_path, $stdout_ref, $stderr_ref ) = @_;
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$cmd = expand_vars($cmd);
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my ( $prev_path, $prev_wdir );
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@@ -1015,6 +1032,7 @@ sub call_shell {
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10161033
sub call_system {
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my ( $wait_key, $cmd ) = @_;
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$cmd = expand_vars($cmd);
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my ($res);
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def_prog_mode();
@@ -2167,6 +2185,27 @@ sub load_config {
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}
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last SWITCH;
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}
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elsif (/^VARIABLES$/) {
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# User-defined config variables (FEATURE-REQUESTS
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# item 3): `NAME = value` lines, collected raw here
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# and resolved (cross-references expanded) once after
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# all config files are read. Names are kept
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# case-sensitively (they are referenced as $NAME in
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# actions); a value may be optionally quoted.
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foreach my $line ( split /\s*\n\s*/, $val ) {
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next if $line =~ /^\s*$/;
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my ( $vn, $vv ) = split /\s*=\s*/, $line, 2;
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next
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unless defined $vn and $vn =~ /^\w+$/;
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$vv //= '';
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$vv =~ s/^\s+//;
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$vv =~ s/\s+$//;
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$vv =~ s/^(['"])(.*)\1$/$2/;
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$ctx->{cfg}{vars}{$vn} = $vv;
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}
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last SWITCH;
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}
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else {
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trace("unknown configuration parameter \"$key\"");
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$res = $ES_SYNTAX_ERR;
@@ -2185,6 +2224,31 @@ sub load_config {
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$res = $ES_NOT_FOUND;
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}
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}
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# All config files read: resolve cross-references between user variables
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# ($NAME / ${NAME}) with a few fixpoint passes, so each variable's stored
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# value is fully expanded before actions reference it. A reference to an
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# undefined name is left verbatim; a circular reference stops at the pass
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# cap (and simply stays unresolved rather than looping). (FEATURE-REQUESTS
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# item 3.)
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if ( my $vars = $ctx->{cfg}{vars} ) {
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for ( 1 .. 10 ) {
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my $changed = 0;
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for my $k ( keys %{$vars} ) {
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my $new = $vars->{$k};
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$new =~
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s/\$\{(\w+)\}/ exists $vars->{$1} ? $vars->{$1} : "\${$1}" /ge;
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$new =~
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s/\$(\w+)/ exists $vars->{$1} ? $vars->{$1} : "\$$1" /ge;
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$changed = 1 if $new ne $vars->{$k};
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$vars->{$k} = $new;
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}
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last unless $changed;
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}
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trace( "config variable $_ = \"$vars->{$_}\"", $LOG_NORMAL )
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for sort keys %{$vars};
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}
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return $res;
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}
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@@ -4726,6 +4790,7 @@ ( $cmd, $mwin )
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sub run_browse {
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my ( $title, $cmd, $save_fname, $extra_path ) = @_;
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$cmd = expand_vars($cmd);
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local ($search_string);
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my ( $out_lines, $err_lines );
@@ -5677,11 +5742,12 @@ sub VERSION_MESSAGE {
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endwin();
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system("clear") if $es == $ES_NO_ERR or $es >= $ES_USER_REQ;
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if ( defined( $ctx->{state}{exec_args} ) ) {
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my $exec_args = expand_vars( $ctx->{state}{exec_args} );
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chdir "$ctx->{state}{SCREEN_DIR}";
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trace( "Changed CWD from $prev_wdir to " . getcwd() );
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trace("exec \"$ctx->{state}{exec_args}\"");
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trace("exec \"$exec_args\"");
56835749
if ( $ctx->{cfg}{RESTRICTED} ) {
5684-
my @argv = shellwords( $ctx->{state}{exec_args} ); # TD-1c
5750+
my @argv = shellwords($exec_args); # TD-1c
56855751
exec { $argv[0] } @argv if @argv;
56865752
}
56875753

@@ -5690,9 +5756,9 @@ sub VERSION_MESSAGE {
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# explanation (FEATURE-REQUESTS item 6; the pre-flight modal catches the
56915757
# common case while the TUI is still up). The `or do` keeps the failure
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# path in the same statement (no "unreachable code after exec" warning).
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exec( $ctx->{state}{exec_args} ) or do {
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exec($exec_args) or do {
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my $err = $!;
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my ($prog) = shellwords( $ctx->{state}{exec_args} );
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my ($prog) = shellwords($exec_args);
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print STDERR "$CALLNAME: cannot execute \"$prog\": $err\n";
56975763
exit 127;
56985764
};

‎src/demo.d/vars.form‎

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@@ -0,0 +1,23 @@
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#
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# CCFE demo: static interpolating config variables.
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# The list_cmd and the action below reference variables defined in the
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# variables {} section of ccfe.conf ($DEMO_HELLO, $LIST_DIR). %{FILE} is the
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# usual form-field substitution; $... names a config variable.
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#
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title {
8+
Config variables demo
9+
}
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top {
11+
Press <F2> on the field to list files (the list_cmd uses $LIST_DIR),
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pick one, then <Enter> -- the action greets you using $DEMO_HELLO.
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}
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field {
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id = FILE
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label = A file from the configured directory (F2 lists it)
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len = 36
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list_cmd = command:single-val:ls $LIST_DIR
19+
}
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action { run:
21+
echo "$DEMO_HELLO"
22+
echo "You picked: %{FILE}"
23+
}

‎src/demo.menu/vars.item‎

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@@ -0,0 +1,5 @@
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item {
2+
id = VARS
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descr = Config variables demo (uses ccfe.conf variables {})
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action = form:demo.d/vars
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}

‎src/man/ccfe.conf.5‎

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Original file line numberDiff line numberDiff line change
@@ -396,6 +396,57 @@ Example:
396396
Required: No
397397

398398

399+
.SH VARIABLES CONFIGURATION SECTION
400+
The optional
401+
.B variables {}
402+
block defines named values that menu and form authors can reference, to avoid
403+
repeating the same path or command fragment across many objects. Each line is a
404+
.B NAME = value
405+
pair; the value may be optionally quoted and may reference other variables with
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.BR $NAME " or " ${NAME} \fR.
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Inter-variable references are resolved once, when the configuration is loaded
408+
(so order does not matter), and a reference to an undefined name is left
409+
verbatim.
410+
.PP
411+
In a menu or form
412+
.BR action " and in a field's " list_cmd
413+
command, every
414+
.BR $NAME / ${NAME}
415+
that names a defined variable is replaced with its value before the command
416+
runs; any other
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.B $...
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(for example
419+
.BR $HOME )
420+
is left untouched for the shell. Variable names are case-sensitive and consist
421+
of letters, digits and underscores.
422+
.PP
423+
Example:
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.PP
425+
.nf
426+
\fC variables {
427+
DOCKER_DIR = /srv/docker
428+
COMPOSE = cd $DOCKER_DIR && docker compose
429+
}\fP
430+
.fi
431+
.PP
432+
A menu item could then use
433+
.BR "action = run:$COMPOSE up -d" \fR,
434+
which runs
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.BR "cd /srv/docker && docker compose up -d" \fR.
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.PP
437+
.B Security note:
438+
the substitution writes the variable's value into the command string, so the
439+
variables are as trusted as the menus and forms themselves. Under
440+
.B restricted
441+
mode the configuration is locked to system-owned files, so unprivileged users
442+
cannot define or change them; and the restricted command allow-list is still
443+
checked against the command as written, so a bare
444+
.B $VAR
445+
program name is refused unless allow-listed.
446+
.PP
447+
Required: No
448+
449+
399450
.SH FORM CONFIGURATION SECTION
400451
The
401452
.B form_global {}

‎src/t/34-config-vars.t‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,79 @@
1+
#!/usr/bin/perl
2+
#
3+
# Static interpolating config variables (FEATURE-REQUESTS item 3).
4+
#
5+
# A `variables { }` config section defines NAME = value pairs that may reference
6+
# each other ($NAME / ${NAME}); the references are resolved once at config load.
7+
# In menu/form actions and list_cmd commands, $NAME is then substituted with the
8+
# resolved value (only defined names; any other $... is left for the shell).
9+
# This drives all three: a cross-referenced variable in a run: action, the
10+
# pass-through of an undefined $VAR to the shell, and a variable in a list_cmd.
11+
#
12+
use strict;
13+
use warnings;
14+
use FindBin qw($Bin);
15+
use lib "$Bin/lib";
16+
use File::Temp qw(tempdir);
17+
use Test::More;
18+
19+
my $src = "$Bin/..";
20+
21+
eval { require CCFE::Test::Pty; 1 } or plan skip_all => "pty helper: $@";
22+
plan skip_all => 'no Linux pseudo-terminal' unless CCFE::Test::Pty->available;
23+
plan skip_all => 'Curses not installed' unless eval { require Curses; 1 };
24+
plan skip_all => 'no installer' unless -f "$src/install.sh";
25+
26+
my $prefix = tempdir( CLEANUP => 1 );
27+
my $log = `cd "$src" && sh install.sh -b -p "$prefix" 2>&1`;
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plan skip_all => "install failed: $log" unless $? == 0 && -x "$prefix/bin/ccfe";
29+
30+
# Append a variables{} section with a cross-reference to the system config.
31+
my $conf = "$prefix/etc/ccfe.conf";
32+
open( my $cf, '>>', $conf ) or plan skip_all => "conf: $!";
33+
print {$cf} "\nvariables {\n BASE_DIR = /tmp\n"
34+
. " MSG = captured from \${BASE_DIR}\n}\n";
35+
close($cf);
36+
37+
my $objs = "$prefix/share/ccfe/objects/ccfe";
38+
open( my $fh, '>', "$objs/vars.form" ) or plan skip_all => "write: $!";
39+
print {$fh} <<'FORM';
40+
title { Vars test }
41+
field {
42+
id = PICK
43+
label = Pick
44+
len = 24
45+
list_cmd = command:single-val:echo $MSG
46+
}
47+
action { run:echo "$MSG ; home=$HOME" }
48+
FORM
49+
close($fh);
50+
51+
plan tests => 3;
52+
53+
# --- run: action: cross-referenced variable + shell pass-through ----------
54+
my $p = CCFE::Test::Pty->spawn( 80, 24, "$prefix/bin/ccfe", 'vars' );
55+
$p->pump(1.2);
56+
$p->send("\r"); # submit -> run -> output browser
57+
$p->pump(1.3);
58+
my $out = $p->screen;
59+
like( $out, qr{captured from /tmp},
60+
'a cross-referenced $\{VAR} resolves in a run: action' );
61+
like( $out, qr{home=/\w},
62+
' an undefined $VAR is left for the shell to expand ($HOME)' );
63+
$p->send("\e");
64+
$p->pump(0.2);
65+
$p->send("\e");
66+
$p->pump(0.2);
67+
68+
# --- list_cmd command: a variable resolves there too (exec_command) -------
69+
my $f = CCFE::Test::Pty->spawn( 80, 24, "$prefix/bin/ccfe", 'vars' );
70+
$f->pump(1.2);
71+
$f->send("\eOQ"); # F2 = list
72+
$f->pump(0.8);
73+
like( $f->screen, qr{captured from /tmp},
74+
'a variable resolves in a list_cmd command' );
75+
$f->send("\e");
76+
$f->pump(0.2);
77+
$f->send("\e");
78+
$f->pump(0.2);
79+
$f->send("\e");

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