Class: ERB::Compiler
- Inherits:
-
Object
- Object
- ERB::Compiler
- Defined in:
- lib/erb.rb
Overview
ERB::Compiler
Compiles ERB templates into Ruby code; the compiled code produces the template result when evaluated. ERB::Compiler provides hooks to define how generated output is handled.
Internally ERB does something like this to generate the code returned by ERB#src:
compiler = ERB::Compiler.new('<>')
compiler.pre_cmd = ["_erbout=''"]
compiler.put_cmd = "_erbout.concat"
compiler.insert_cmd = "_erbout.concat"
compiler.post_cmd = ["_erbout"]
code, enc = compiler.compile("Got <%= obj %>!\n")
puts code
Generates:
#coding:UTF-8
_erbout=''; _erbout.concat "Got "; _erbout.concat(( obj ).to_s); _erbout.concat "!\n"; _erbout
By default the output is sent to the print method. For example:
compiler = ERB::Compiler.new('<>')
code, enc = compiler.compile("Got <%= obj %>!\n")
puts code
Generates:
#coding:UTF-8
print "Got "; print(( obj ).to_s); print "!\n"
Evaluation
The compiled code can be used in any context where the names in the code correctly resolve. Using the last example, each of these print ‘Got It!’
Evaluate using a variable:
obj = 'It'
eval code
Evaluate using an input:
mod = Module.new
mod.module_eval %{
def get(obj)
#{code}
end
}
extend mod
get('It')
Evaluate using an accessor:
klass = Class.new Object
klass.class_eval %{
attr_accessor :obj
def initialize(obj)
@obj = obj
end
def get_it
#{code}
end
}
klass.new('It').get_it
Good! See also ERB#def_method, ERB#def_module, and ERB#def_class.
Defined Under Namespace
Classes: Buffer, PercentLine, Scanner, SimpleScanner, TrimScanner
Instance Attribute Summary collapse
-
#insert_cmd ⇒ Object
The command to handle text that is inserted prior to a newline.
-
#percent ⇒ Object
readonly
Returns the value of attribute percent.
-
#post_cmd ⇒ Object
An array of commands appended to compiled code.
-
#pre_cmd ⇒ Object
An array of commands prepended to compiled code.
-
#put_cmd ⇒ Object
The command to handle text that ends with a newline.
-
#trim_mode ⇒ Object
readonly
Returns the value of attribute trim_mode.
Instance Method Summary collapse
- #add_insert_cmd(out, content) ⇒ Object
- #add_put_cmd(out, content) ⇒ Object
-
#compile(s) ⇒ Object
Compiles an ERB template into Ruby code.
-
#content_dump(s) ⇒ Object
:nodoc:.
-
#initialize(trim_mode) ⇒ Compiler
constructor
Construct a new compiler using the trim_mode.
-
#make_scanner(src) ⇒ Object
:nodoc:.
-
#prepare_trim_mode(mode) ⇒ Object
:nodoc:.
Constructor Details
#initialize(trim_mode) ⇒ Compiler
Construct a new compiler using the trim_mode. See ERB::new for available trim modes.
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# File 'lib/erb.rb', line 692 def initialize(trim_mode) @percent, @trim_mode = prepare_trim_mode(trim_mode) @put_cmd = 'print' @insert_cmd = @put_cmd @pre_cmd = [] @post_cmd = [] end |
Instance Attribute Details
#insert_cmd ⇒ Object
The command to handle text that is inserted prior to a newline
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# File 'lib/erb.rb', line 705 def insert_cmd @insert_cmd end |
#percent ⇒ Object (readonly)
Returns the value of attribute percent
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# File 'lib/erb.rb', line 699 def percent @percent end |
#post_cmd ⇒ Object
An array of commands appended to compiled code
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# File 'lib/erb.rb', line 711 def post_cmd @post_cmd end |
#pre_cmd ⇒ Object
An array of commands prepended to compiled code
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# File 'lib/erb.rb', line 708 def pre_cmd @pre_cmd end |
#put_cmd ⇒ Object
The command to handle text that ends with a newline
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# File 'lib/erb.rb', line 702 def put_cmd @put_cmd end |
#trim_mode ⇒ Object (readonly)
Returns the value of attribute trim_mode
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# File 'lib/erb.rb', line 699 def trim_mode @trim_mode end |
Instance Method Details
#add_insert_cmd(out, content) ⇒ Object
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# File 'lib/erb.rb', line 591 def add_insert_cmd(out, content) out.push("#{@insert_cmd}((#{content}).to_s)") end |
#add_put_cmd(out, content) ⇒ Object
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# File 'lib/erb.rb', line 587 def add_put_cmd(out, content) out.push("#{@put_cmd} #{content_dump(content)}") end |
#compile(s) ⇒ Object
Compiles an ERB template into Ruby code. Returns an array of the code and encoding like [“code”, Encoding].
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# File 'lib/erb.rb', line 597 def compile(s) enc = s.encoding raise ArgumentError, "#{enc} is not ASCII compatible" if enc.dummy? s = s.b # see String#b enc = detect_magic_comment(s) || enc out = Buffer.new(self, enc) content = '' scanner = make_scanner(s) scanner.scan do |token| next if token.nil? next if token == '' if scanner.stag.nil? case token when PercentLine add_put_cmd(out, content) if content.size > 0 content = '' out.push(token.to_s) out.cr when :cr out.cr when '<%', '<%=', '<%#' scanner.stag = token add_put_cmd(out, content) if content.size > 0 content = '' when "\n" content << "\n" add_put_cmd(out, content) content = '' when '<%%' content << '<%' else content << token end else case token when '%>' case scanner.stag when '<%' if content[-1] == ?\n content.chop! out.push(content) out.cr else out.push(content) end when '<%=' add_insert_cmd(out, content) when '<%#' # out.push("# #{content_dump(content)}") end scanner.stag = nil content = '' when '%%>' content << '%>' else content << token end end end add_put_cmd(out, content) if content.size > 0 out.close return out.script, enc end |
#content_dump(s) ⇒ Object
:nodoc:
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# File 'lib/erb.rb', line 578 def content_dump(s) # :nodoc: n = s.count("\n") if n > 0 s.dump + "\n" * n else s.dump end end |
#make_scanner(src) ⇒ Object
:nodoc:
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# File 'lib/erb.rb', line 686 def make_scanner(src) # :nodoc: Scanner.make_scanner(src, @trim_mode, @percent) end |
#prepare_trim_mode(mode) ⇒ Object
:nodoc:
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# File 'lib/erb.rb', line 662 def prepare_trim_mode(mode) # :nodoc: case mode when 1 return [false, '>'] when 2 return [false, '<>'] when 0 return [false, nil] when String perc = mode.include?('%') if mode.include?('-') return [perc, '-'] elsif mode.include?('<>') return [perc, '<>'] elsif mode.include?('>') return [perc, '>'] else [perc, nil] end else return [false, nil] end end |