Feature #10395: erb: allow variables to be set from the command line

• Status: Closed
• Assignee: seki (Masatoshi Seki)
• Target version: -

[josb (Jos Backus)]

This would make erb more useful from the command line. Granted the use of Binding#eval is dangerous so one has to be careful. Newer versions of Ruby have Binding#local_variable_set which can be used instead but this works with Ruby 2.0.0.

jonagold:local jos$ cat /tmp/erb-template
This is <%= foo %>
And this is <%= bar %>

jonagold:local jos$ diff -u /usr/bin/erb /tmp/erb
--- /usr/bin/erb	2014-05-15 22:14:36.000000000 -0700
+++ /tmp/erb	2014-10-16 22:29:37.000000000 -0700
@@ -114,6 +114,13 @@
         exit 1
       end

+      vars = ARGV.take_while {|arg| arg[/^\w+=/]}
+      ARGV.slice!(0, vars.size)
+      vars.each do |var|
+        k, v = var.split('=', 2)
+        TOPLEVEL_BINDING.eval %Q(#{k} = "#{v}")
+      end
+
       $<.set_encoding(Encoding::ASCII_8BIT, nil)
       src = $<.read
       filename = $FILENAME

jonagold:local jos$ /tmp/erb foo=FOO bar=123 /tmp/erb-template
This is FOO
And this is 123
jonagold:local jos$

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)
• Status changed from Open to Assigned
• Assignee set to seki (Masatoshi Seki)
• Target version set to Ruby 2.2.0

No new features for maintenance branches.
And your patch doesn't allow options after variables.

https://github.com/nobu/ruby/compare/Feature%2310395-erb-variables-from-commandline

[josb (Jos Backus)]

Thanks Nobu, that looks like a much better implementation. Appreciate your help.

[nobu (Nobuyoshi Nakada)]

• Status changed from Assigned to Closed
• % Done changed from 0 to 100

Applied in changeset ruby-trunk:r48786.

---

erb: set variables from the command line

• bin/erb (ARGV.switch, ERB::Main#run): allow variables to be set
  from the command line. [ruby-core:65772] [Feature #10395]

[hsbt (Hiroshi SHIBATA)]

• Project changed from 14 to Ruby master
• Target version deleted (Ruby 2.2.0)