Class: Opal::Nodes::BlockNode

Inherits:
Base show all
Defined in:
opal/lib/opal/nodes/definitions.rb

Constant Summary

Constants included from Helpers

Helpers::RESERVED

Instance Attribute Summary

Attributes inherited from Base

#compiler, #type

Instance Method Summary collapse

Methods inherited from Base

#add_ivar, #add_local, #add_temp, children, #children, #compile_to_fragments, #error, #expr, #expr?, #expr_or_nil, #fragment, handle, handlers, #helper, #in_while?, #initialize, #process, #push, #recv, #recv?, #s, #scope, #stmt, #stmt?, #unshift, #while_loop, #with_temp, #wrap

Methods included from Helpers

#current_indent, #empty_line, #indent, #js_falsy, #js_truthy, #js_truthy_optimize, #line, #lvar_to_js, #mid_to_jsid, #property, #reserved?, #variable

Constructor Details

This class inherits a constructor from Opal::Nodes::Base

Instance Method Details

#child_is_expr?(child) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'opal/lib/opal/nodes/definitions.rb', line 108

def child_is_expr?(child)
  raw_expression?(child) and [:stmt, :stmt_closure].include?(@level)
end

#compile ⇒ Object 



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# File 'opal/lib/opal/nodes/definitions.rb', line 88

def compile
  return push "nil" if children.empty?

  children.each_with_index do |child, idx|
    push stmt_join unless idx == 0

    if yasgn = find_inline_yield(child)
      push compiler.process(yasgn, @level)
      push ";"
    end

    push compiler.process(child, @level)
    push ";" if child_is_expr?(child)
  end
end

#find_inline_yield(stmt) ⇒ Sexp

When a block sexp gets generated, any inline yields (i.e. yield statements that are not direct members of the block) need to be generated as a top level member. This is because if a yield is returned by a break statement, then the method must return.

As inline expressions in javascript cannot return, the block must be rewritten.

For example, a yield inside an array:

[1, 2, 3, yield(4)]

Must be rewitten into:

tmp = yield 4
[1, 2, 3, tmp]

This rewriting happens on sexps directly.

Parameters:

  • stmt (Sexp) —

    sexps to (maybe) rewrite

Returns:



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# File 'opal/lib/opal/nodes/definitions.rb', line 137

def find_inline_yield(stmt)
  found = nil
  case stmt.first
  when :js_return
    if found = find_inline_yield(stmt[1])
      found = found[2]
    end
  when :array
    stmt[1..-1].each_with_index do |el, idx|
      if el.first == :yield
        found = el
        stmt[idx+1] = s(:js_tmp, '$yielded')
      end
    end
  when :call
    arglist = stmt[3]
    arglist[1..-1].each_with_index do |el, idx|
      if el.first == :yield
        found = el
        arglist[idx+1] = s(:js_tmp, '$yielded')
      end
    end
  end

  if found
    scope.add_temp '$yielded' unless scope.has_temp? '$yielded'
    s(:yasgn, '$yielded', found)
  end
end

#raw_expression?(child) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'opal/lib/opal/nodes/definitions.rb', line 112

def raw_expression?(child)
  ![:xstr, :dxstr].include?(child.type)
end

#stmt_join ⇒ Object 



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# File 'opal/lib/opal/nodes/definitions.rb', line 104

def stmt_join
  scope.class_scope? ? "\n\n#{current_indent}" : "\n#{current_indent}"
end