Class: Eggshell::ExpressionEvaluator

Inherits:
Object
  • Object
show all
Defined in:
lib/eggshell/expression-evaluator.rb,
lib/eggshell/expression-evaluator/lexer.rb,
lib/eggshell/expression-evaluator/parser.rb,
lib/eggshell/expression-evaluator/evaluator.rb

Defined Under Namespace

Modules: Parser Classes: Evaluator, Lexer

Constant Summary collapse

ESCAPE_MAP = 
{
	'\\n'=> "\n",
	'\\r' => "\r",
	'\\t' => "\t",
	"\\(" => "(",
	"\\)" => ")",
	"\\{" => "{",
	"\\}" => "}",
	"\\[" => "[",
	"\\]" => "]",
	"\\'" => "'",
	'\\"' => '"'
}.freeze
OPERATOR_MAP = 
{
	'='.to_sym => 1000,
	'=='.to_sym => 999,
	'!='.to_sym => 999,
	'<'.to_sym => 990,
	'<='.to_sym => 990,
	'>'.to_sym => 990,
	'>='.to_sym => 990,
	'?'.to_sym => 900,
	':'.to_sym => 899,
	'<<'.to_sym => 200,
	'>>'.to_sym => 200,
	'~'.to_sym => 200,
	'&'.to_sym => 200,
	'|'.to_sym => 199,
	'*'.to_sym => 150,
	'/'.to_sym => 150,
	'%'.to_sym => 150,
	'^'.to_sym => 150,
	'+'.to_sym => 100,
	'-'.to_sym => 100,
	'&&'.to_sym => 99,
	'||'.to_sym => 99
}.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(vars = nil, funcs = nil) ⇒ ExpressionEvaluator 



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# File 'lib/eggshell/expression-evaluator.rb', line 44

def initialize(vars = nil, funcs = nil)
	@vars = vars || {}
	@funcs = funcs || {}
	@cache = {}
	@parser = Parser::DefaultParser.new
	#@evaluator = Evaluator.new(@vars, @funcs)
end

Instance Attribute Details

#funcs ⇒ Object (readonly)

Returns the value of attribute funcs.



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# File 'lib/eggshell/expression-evaluator.rb', line 79

def funcs
  @funcs
end

#parser ⇒ Object (readonly)

Returns the value of attribute parser.



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# File 'lib/eggshell/expression-evaluator.rb', line 79

def parser
  @parser
end

#vars ⇒ Object (readonly)

Returns the value of attribute vars.



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# File 'lib/eggshell/expression-evaluator.rb', line 79

def vars
  @vars
end

Class Method Details

.op_eval(lop, op, rop) ⇒ Object 



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# File 'lib/eggshell/expression-evaluator.rb', line 184

def self.op_eval(lop, op, rop)
	if (lop.is_a?(Numeric) && rop.is_a?(Numeric)) || lop.is_a?(rop.class)
		op = op.to_s
		case op
		when '==='
			return lop === rop
		when '=='
			return lop == rop
		when '!='
			return lop != rop
		when '+'
			return lop + rop
		when '-'
			return lop - rop
		when '/'
			return lop / rop
		when '*'
			return lop * rop
		when '<<'
			return lop << rop
		when '>>'
			return lop >> rop
		when '<'
			return lop < rop
		when '<='
			return lop <= rop
		when '>'
			return lop > rop
		when '>='
			return lop >= rop
		when '|'
			return lop | rop
		when '||'
			return lop || rop
		when '&'
			return lop & rop
		when '&&'
			return lop && rop
		when '%'
			return lop % rop
		when '^'
			return lop ^ rop
		when '='
			# @todo assign rop to lop
		end
	else
		
	end
end

Instance Method Details

#evaluate(statement, do_parse = true, cache = true, vtable = nil, ftable = nil) ⇒ Object 



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# File 'lib/eggshell/expression-evaluator.rb', line 90

def evaluate(statement, do_parse = true, cache = true, vtable = nil, ftable = nil)
	vtable = @vars if !vtable.is_a?(Hash)
	ftable = @funcs if !ftable.is_a?(Hash)
	parsed = statement

	if !statement.is_a?(Array)
		return statement if !do_parse || !statement.is_a?(String)
		parsed = parse(statement, cache)
	end

	ret = nil
	parsed.each do |frag|
		ftype = frag[0]
		if ftype == :op
			op_val = frag[1][0].is_a?(Array) ? evaluate([frag[1][0]], false) : frag[1][0]
			z = 1
			while z < frag[1].length
				op = frag[1][z]
				rop = frag[1][z+1]
				rop = evaluate([rop]) if rop.is_a?(Array)
				op_val = self.class.op_eval(op_val, op, rop)
				z += 2
			end
			ret = op_val
		elsif ftype == :op_tern
			cond = frag[1].is_a?(Array) ? evaluate(frag[1]) : frag[1]
			if cond
				ret = frag[2].is_a?(Array) ? evaluate(frag[2], false) : frag[2]
			else
				ret = frag[3].is_a?(Array) ? evaluate(frag[3], false) : frag[3]
			end
		elsif ftype == :func
			fname = frag[1]
			ns, name = fname.split(':')
			if !name
				name = ns
				ns = ':'
				fname = ':' + name
			else
				ns += ':'
			end

			handler = ftable[fname]
			if !handler && ftable[ns]
				handler = ftable[ns]
			end
			
			_args = []
			frag[2].each do |ele|
				_args << (ele.is_a?(Array) && ele[0].is_a?(Symbol) ? evaluate([ele]) : ele)
			end
			
			# 1. check for exact func name
			# 2. check for :exec_func
			if handler.respond_to?(name.to_sym)
				ret = handler.send(name.to_sym, *frag[2])
			elsif handler.respond_to?(:exec_func)
				ret = handler.exec_func(name, frag[2])
			end
		elsif ftype == :var
			ret = var_get(frag, false, vtable)
		elsif ftype == :group
			ret = evaluate(frag[1], false, cache, vtable)
		elsif ftype == :array
			arr = []
			i = 1
			while i < frag.length
				arr << (frag[i].is_a?(Array) ? evaluate(frag[i]) : frag[i])
				i += 1
			end
			ret = arr
		elsif ftype == :hash
			map = {}
			i = 1
			while i < frag.length
				k = frag[i]
				v = frag[i+1]
				k = evaluate(k) if k.is_a?(Array) && k[0].is_a?(Symbol)
				v = evaluate(v) if v.is_a?(Array) && v[0].is_a?(Symbol)
				map[k] = v
				i += 2
			end
			ret = map
		elsif !ftype.is_a?(Symbol)
			# assumes a literal
			ret = ftype
		end
	end
	
	ret
end

#parse(statement, cache = true) ⇒ Object 



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# File 'lib/eggshell/expression-evaluator.rb', line 81

def parse(statement, cache = true)
	parsed = @cache[statement]
	return parsed if cache && parsed

	parsed = @parser.parse(statement)
	@cache[statement] = parsed if cache
	return parsed
end

#register_functions(handler, names = nil, ns = '') ⇒ Object

TODO:

expand mapping of functions so that we don’t have to check each

Maps 1 or more virtual function names to a handler.

Virtual functions take the form of ‘funcname` or `ns:funcname`. When registering functions, all function names will be mapped to the same namespace that’s passed in. If no names are given, the handler will be set to handle all function calls in the namespace.

The handler should either handle 1-to-1 function calls (e.g. ‘ns:func` goes to `handler.func()`) or it should contain the following method signature: `def exec_func(funcname, args = [])`. If there’s a 1-to-1 match, arguments are expanded into individual arguments instead of an array.

time a func is referenced whether handler can handle it (only applies to explicit names)



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# File 'lib/eggshell/expression-evaluator.rb', line 68

def register_functions(handler, names = nil, ns = '')
	names = names.split(',') if names.is_a?(String) && names.strip != ''
	if names.is_a?(Array)
		names.each do |name|
			@funcs["#{ns}:#{name}"] = handler
		end
	else
		@funcs["#{ns}:"] = handler
	end
end

#test_func(*args) ⇒ Object 



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# File 'lib/eggshell/expression-evaluator.rb', line 302

def test_func(*args)
	puts "test_func: #{args.inspect}"
end

#var_get(var, do_ptr = false, vtable = nil) ⇒ Object 



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# File 'lib/eggshell/expression-evaluator.rb', line 234

def var_get(var, do_ptr = false, vtable = nil)
	vtable = @vars if !vtable
	if var.is_a?(String)
		if var.match(/^[a-zA-Z_][a-zA-Z0-9_\.]*$/)
			return vtable[var] if vtable.has_key?(var)
		end
		var = @parser.parse(var)
	end

	ptr_lst = nil
	ptr = vtable

	i = 0
	parts = var
	# @todo if do_ptr, set it as parts.length - 1? (and avoid having to save ptr_lst)
	while (i < parts.length)
		part = parts[i]
		ptr_lst = ptr
		if part == :var
			key = parts[i+1]
			if ptr.is_a?(Hash) && ptr[key]
				ptr = ptr[key]
				if ptr != nil
					i += 2
					next
				else
					break
				end
			else
				ptr = nil
				break
			end
		elsif part[0] == :index_access
			idx = part[1]
			if idx.is_a?(Array)
				idx = var_get(idx)
				if idx == nil
					ptr = nil
					break
				end
			end
			if (ptr.is_a?(Array) || ptr.is_a?(Hash)) && ptr[idx]
				ptr = ptr[idx]
			else
				ptr = nil
				break
			end
		elsif part[0] == :member_access
			mname = 'get_' + part[1]
			if ptr.respond_to?(mname.to_sym)
				ptr = ptr.send(mname.to_sym)
			else
				ptr = nil
				break
			end
		elsif part[0] == :func
			ptr = evaluate(part, false)
			break if ptr == nil
		end
		i += 1
	end
	
	return do_ptr ? ptr_lst : ptr
end

#var_set(var, val) ⇒ Object 



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# File 'lib/eggshell/expression-evaluator.rb', line 299

def var_set(var, val)
end