Class: Loxxy::BackEnd::Environment

Inherits:
Object
  • Object
show all
Defined in:
lib/loxxy/back_end/environment.rb

Overview

A environment is a name space that corresponds either to a specific delimited region in Loxxy source code or to an activation record of a relation or a relation definition. It contains a map of names to the objects they name (e.g. logical var)

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(aParent = nil) ⇒ Environment

Construct a environment instance.

Parameters:

  • aParent (Environment, NilClass) (defaults to: nil) —

    Parent environment to this one.



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# File 'lib/loxxy/back_end/environment.rb', line 33

def initialize(aParent = nil)
  @enclosing = aParent
  @defns = {}
  @expr_stack = []
end

Instance Attribute Details

#defns ⇒ Hash{String => Variable} (readonly)

Mapping from user-defined name to related definition (say, a variable object)

Returns:

  • (Hash{String => Variable}) —

    Pairs of the kind



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# File 'lib/loxxy/back_end/environment.rb', line 26

def defns
  @defns
end

#embedding ⇒ Boolean

Returns true if this environment is part of a closure (contains an embedded function).

Returns:

  • (Boolean) —

    true if this environment is part of a closure (contains an embedded function)



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# File 'lib/loxxy/back_end/environment.rb', line 21

def embedding
  @embedding
end

#enclosing ⇒ Environment, NilClass

The enclosing (parent) environment.

Returns:



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# File 'lib/loxxy/back_end/environment.rb', line 14

def enclosing
  @enclosing
end

#expr_stack ⇒ Array<LoxNode> (readonly)

Returns stack of values needed in evaluating an expression.

Returns:

  • (Array<LoxNode>) —

    stack of values needed in evaluating an expression



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# File 'lib/loxxy/back_end/environment.rb', line 29

def expr_stack
  @expr_stack
end

#predecessor ⇒ Environment, NilClass

The previous environment in the environment chain.

Returns:



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# File 'lib/loxxy/back_end/environment.rb', line 18

def predecessor
  @predecessor
end

Instance Method Details

#insert(anEntry) ⇒ BackEnd::Variable

Add a new variable to the environment.

Parameters:

Returns:



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# File 'lib/loxxy/back_end/environment.rb', line 42

def insert(anEntry)
  e = validated_entry(anEntry)
  defns[e.name] = e

  e
end

#inspect ⇒ String

Returns a string with a human-readable representation of the object.

Returns:

  • (String) 


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# File 'lib/loxxy/back_end/environment.rb', line 51

def inspect
  +"#<#{self.class}:#{object_id.to_s(16)}>"
end