From a5523ff7e70f3386b4814c2157230c2a0034f2cb Mon Sep 17 00:00:00 2001
From: b <rowerynaksiezycu@gmail.com>
Date: Thu, 21 Sep 2023 20:55:17 +0000
Subject: [PATCH] Conditional statements.

---
 configure.1.pl | 109 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 93 insertions(+), 16 deletions(-)

diff --git a/configure.1.pl b/configure.1.pl
index c452067..806f3cc 100755
--- a/configure.1.pl
+++ b/configure.1.pl
@@ -296,6 +296,31 @@
 #     $0 - the name of the setting
 #   More functions and values can be added in future versions.
 #
+# The settings can be conditional thanks to using statements like:
+#    if
+#    else
+#    endif
+# 
+# Anything after the "if" keyword is the codition to check.
+# Condition is considered true if its value is not an empty string
+# Condition is parsed the same way as a dynamic setting definition
+#
+# Conditional statements must start at from first column in the line.
+# Conditional statements can be nested
+# 
+# Example:
+#   s1: 1
+#   if $s1
+#   s3 = $s1
+#   if $s2
+#   s3 = $s2
+#   endif
+#   else
+#   s3: 0
+#   endif
+# Here the value of s3 is '1'.
+# 
+#
 # Inserting settings to source files:
 #
 # After all settings are read, the actual source is processed line by line.
@@ -980,6 +1005,8 @@ sub parse_file {
 	my $parse_mode = 0;
 	my $name = '';
 	my $value = '';
+	my $if_depth = 0;
+	my $if_block = 0;
 
 	while (defined(my $line = <$file>)) {
 		$line =~ s/[\r\n]//g;
@@ -989,40 +1016,90 @@ sub parse_file {
 		# new definition name: value
 		if ($line =~ /^([A-Za-z0-9_\-\.]+):[ \t](.*)$/) {
 			$parse_mode = 0;
-			$name = $1;
-			$value = $2;
-			$cfg{$name} = '';
-			print_debug($depth, "STATIC DEFINE $name=$value")
+			unless ($if_block) {
+				$name = $1;
+				$value = $2;
+				$cfg{$name} = '';
+				print_debug($depth, "STATIC DEFINE $name=$value")
+			}
 		}
 		# new definition name = value
 		elsif ($line =~ /^([A-Za-z0-9_\-\.]+)[ \t]*=(.*)$/) {
 			$parse_mode = 1;
-			$name = $1;
-			$value = $2;
-			$cfg{$name} = '';
-			print_debug($depth, "DYNAMIC DEFINE $name=$value")
+			unless ($if_block) {
+				$name = $1;
+				$value = $2;
+				$cfg{$name} = '';
+				print_debug($depth, "DYNAMIC DEFINE $name=$value")
+			}
 		}
 		# continued definition
 		elsif ($line =~ /^[ \t](.*)$/) {
-			$value = "\n".$1;
-			print_debug($depth, "CONTINUE $name $value")
+			unless ($if_block) {
+				$value = "\n".$1;
+				print_debug($depth, "CONTINUE $name $value")
+			}
 		}
 		# include file
-		elsif ($line =~ /^include[ \t]+([^ \t](.*[^ \t])?)[ \t]*$/)
-		{
-			my $path = parse_value($1, $depth+1, %cfg);
-			print_debug($depth, "INCLUDE $path");
-			%cfg = parse_file($path, $encoding, $depth+1, %cfg);
+		elsif ($line =~ /^include[ \t]+([^ \t](.*[^ \t])?)[ \t]*$/) {
+			unless ($if_block) {
+				my $path = parse_value($1, $depth+1, %cfg);
+				print_debug($depth, "INCLUDE $path");
+				%cfg = parse_file($path, $encoding, $depth+1, %cfg);
+				$name = '';
+				$value = '';
+			}
+		}
+		# if
+		elsif ($line =~ /^if[ \t]+([^ \t](.*[^ \t])?)[ \t]*$/) {
+			$if_depth += 1;
+			unless ($if_block) {
+				my $cond = parse_value($1, $depth+1, %cfg);
+				print_debug($depth, "IF.$if_depth $cond");
+				unless ($cond ne '') {
+					$if_block = $if_depth;
+				}
+			}
+			$name = '';
+			$value = '';
+		}
+		# endif
+		elsif ($line =~ /^endif([ \t].*)?$/) {
+			my $_if_depth = $if_depth;
+			if ($if_depth > 0) {
+				$if_depth -= 1;
+			}
+			if ($if_depth < $if_block) {
+				$if_block = 0;
+			}
+			unless ($if_block) {
+				print_debug($depth, "ENDIF.$_if_depth");
+			}
 			$name = '';
 			$value = '';
 		}
+		# else
+		elsif ($line =~ /^else([ \t].*)?$/) {
+			unless ($if_block) {
+				$if_block = $if_depth;
+				print_debug($depth, "ELSE.$if_depth");
+			}
+			elsif ($if_depth == $if_block) {
+				$if_block = 0;
+				print_debug($depth, "ELSE.$if_depth");
+			}
+			$name = '';
+			$value = '';
+		}
+		# no el(s)if at this point
+		
 		# other line, not understood
 		else {
 			$name = '';
 			$value = '';
 		}
 		
-		if ($name ne '') {
+		if (($name ne '') and (not $if_block)) {
 			if ($parse_mode != 0) {
 				$value = parse_value($value, $depth+1, %cfg);
 			}
-- 
2.30.2