From 0606f5ba62903c0e3042602a9243822e61fe289f Mon Sep 17 00:00:00 2001
From: Don Armstrong <don@donarmstrong.com>
Date: Wed, 10 Apr 2013 09:19:53 -0700
Subject: [PATCH] allow selecting by header name if --has-header is given

---
 col_grep | 111 ++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 81 insertions(+), 30 deletions(-)

diff --git a/col_grep b/col_grep
index 95ba3a7..22d6464 100755
--- a/col_grep
+++ b/col_grep
@@ -59,22 +59,25 @@ Display this manual.
 
 =cut
 
-
+use Scalar::Util qw(looks_like_number);
+use Text::CSV;
 use vars qw($DEBUG);
 
 my %options = (debug            => 0,
-	       help             => 0,
-	       man              => 0,
-	       delimiter        => "\t",
-	       field            => [],
-	       regexp           => [],
+               help             => 0,
+               man              => 0,
+               delimiter        => "\t",
+               field            => [],
+               regexp           => [],
+               has_header       => 0,
 	      );
 
 GetOptions(\%options,
-	   'delimiter=s',
-	   'field|f=s@',
-	   'regexp|e=s@',
-	   'debug|d+','help|h|?','man|m');
+           'delimiter=s',
+           'field|f=s@',
+           'regexp|e=s@',
+           'has_header|has-header!',
+           'debug|d+','help|h|?','man|m');
 
 pod2usage() if $options{help};
 pod2usage({verbose=>2}) if $options{man};
@@ -90,13 +93,19 @@ if (not @{$options{field}}) {
     $options{field} = [1];
 }
 
-my @field_indexes = map { $_ > 0 ? $_ - 1 : $_;}
+my @header;
+my %header;
+if ($options{has_header}) {
+    # we allow for a header
+}
+
+my @field_indexes = map { looks_like_number($_) && $_ > 0 ? $_ - 1 : $_;}
     map {split /,/} @{$options{field}};
 my %field_indexes;
 @field_indexes{@field_indexes} = @field_indexes;
 @field_indexes = values %field_indexes;
 
-if (grep {not /-?\d+/} @field_indexes) {
+if (grep {not /-?\d+/} @field_indexes and not $options{has_header}) {
     push @USAGE_ERRORS,"Invalid field index(es)";
 }
 
@@ -106,26 +115,68 @@ if (not @{$options{regexp}} and @ARGV) {
     push @{$options{regexp}}, shift @ARGV;
 }
 
+if (not @ARGV) {
+    # we'll use this as a special indicator to read stdin
+    push @ARGV,undef;
+}
 my %compiled_regexes;
-LINE: while (<>) {
-    my $chomped = chomp;
-    my $line = $_;
-    my @fields = split /$options{delimiter}/;
-    # skip lines which don't have enough fields
-    next LINE if grep {not defined $_} @fields[@field_indexes];
- REGEX: for my $regex (@{$options{regexp}}) {
-    FIELDS: for my $field (@fields[@field_indexes]) {
-	    if (length $regex) {
-		if (not exists $compiled_regexes{$regex}) {
-		    $compiled_regexes{$regex} = qr/$regex/;
-		}
-		$field =~ $compiled_regexes{$regex} or next LINE;
-	    }
-	}
+my $csv = Text::CSV->new({sep_char=>$options{delimiter}});
+FILE: for my $file (@ARGV) {
+    my $fh;
+    my $headers_updated = 0;
+    if (not defined $file) {
+        $fh = \*STDIN;
+        $file = "STDIN";
+    } else {
+        $fh = IO::File->new($file,'r') or
+            die "Unable to open $file for reading: $!";
+    }
+ LINE: while (<$fh>) {
+        my $chomped = chomp;
+        my $line = $_;
+        die "Unable to parse line $. of $file: ".$csv->error_diag() unless $csv->parse($_);
+        my @fields = $csv->fields();
+        # skip lines which don't have enough fields
+        if ($options{has_header} and not @header) {
+            @header = @fields;
+            @header{@header} = 0..$#fields;
+            print $line;
+            print $/ if $chomped;
+            next LINE;
+        }
+        if ($options{has_header} and not $headers_updated) {
+            $headers_updated = 0;
+            if (@header < @fields) {
+                @header{@header} = 1..@fields;
+            }
+            my @new_indexes;
+            for my $index (@field_indexes) {
+                push @new_indexes,$index and next if $index =~ /^-?\d+$/;
+                if (not exists $header{$index}) {
+                    use Data::Dumper;
+                    print STDERR Dumper(\%header);
+                    print STDERR "Invalid header $index\n";
+                    exit 1;
+                } else {
+                    push @new_indexes,$header{$index};
+                }
+            }
+            @field_indexes = @new_indexes;
+        }
+        next LINE if grep {not defined $_} @fields[@field_indexes];
+    REGEX: for my $regex (@{$options{regexp}}) {
+        FIELDS: for my $field (@fields[@field_indexes]) {
+                if (length $regex) {
+                    if (not exists $compiled_regexes{$regex}) {
+                        $compiled_regexes{$regex} = qr/$regex/;
+                    }
+                    $field =~ $compiled_regexes{$regex} or next LINE;
+                }
+            }
+        }
+        print $line;
+        print $/ if $chomped;
     }
-    print $_;
-    print $/ if $chomped;
 }
 
-
 __END__
-- 
2.39.2