CODEWITHSUNDEEP
ruby
Vijay
Vijay

Reputation: 453

How Ruby Interprets $(foo)

When I read RbConfig::CONFIG['libdir'] it gives me lib folder location. But in rbconfig.rb file CONFIG["libdir"] = "$(exec_prefix)/lib". How the value is interpreted here.

Upvotes: 0

Views: 104

Answers (1)

Stefan
Stefan

Reputation: 114208

$(exec_prefix) refers to a key in RbConfig::CONFIG.

But that's not a Ruby feature. rbconfig.rb contains code to expand these values: every occurrence of $(key) is replaced with the corresponding value of RbConfig::CONFIG['key']

My rbconfig.rb contains these lines:

CONFIG["prefix"]      = (TOPDIR || DESTDIR + "/Users/sos/.rubies/ruby-2.2.2")
CONFIG["exec_prefix"] = "$(prefix)"
CONFIG["libdir"]      = "$(exec_prefix)/lib"

And their values are:

RbConfig::CONFIG["prefix"]      #=> "/Users/sos/.rubies/ruby-2.2.2"
RbConfig::CONFIG["exec_prefix"] #=> "/Users/sos/.rubies/ruby-2.2.2"
RbConfig::CONFIG["libdir"]      #=> "/Users/sos/.rubies/ruby-2.2.2/lib"

Upvotes: 6

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