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Linted symbol_table.rb

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Saf 2020-08-30 13:20:17 -07:00
parent d3ed4e81ec
commit 34cc52c6a8
1 changed files with 41 additions and 75 deletions
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116
lib/n65/symbol_table.rb
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@ -1,128 +1,108 @@
# frozen_string_literal: true
module N65
class SymbolTable
attr_accessor :scope_stack
##### Custom Exceptions
# Custom Exceptions
class InvalidScope < StandardError; end
class UndefinedSymbol < StandardError; end
class CantExitScope < StandardError; end
####
## Initialize a symbol table that begins in global scope
# Initialize a symbol table that begins in global scope
def initialize
@symbols = {
:global => {}
global: {}
}
@anonymous_scope_number = 0
@scope_stack = [:global]
@subroutine_cycles = {}
end
####
## Add a running cycle count to current top level scopes (ie subroutines)
# Add a running cycle count to current top level scopes (ie subroutines)
def add_cycles(cycles)
cycles ||= 0
top_level_subroutine = @scope_stack[1]
unless top_level_subroutine.nil?
@subroutine_cycles[top_level_subroutine] ||= 0
@subroutine_cycles[top_level_subroutine] += cycles
end
return if top_level_subroutine.nil?
@subroutine_cycles[top_level_subroutine] ||= 0
@subroutine_cycles[top_level_subroutine] += cycles
end
####
## Define a new scope, which can be anonymous or named
## and switch into that scope
# Define a new scope, which can be anonymous or named
# and switch into that scope
def enter_scope(name = nil)
name = generate_name if name.nil?
name = name.to_sym
scope = current_scope
if scope.has_key?(name)
fail(InvalidScope, "Scope: #{name} already exists")
end
raise(InvalidScope, "Scope: #{name} already exists") if scope.key?(name)
scope[name] = {}
@scope_stack.push(name)
end
####
## Exit the current scope
# Exit the current scope
def exit_scope
if @scope_stack.size == 1
fail(CantExitScope, "You cannot exit global scope")
end
raise(CantExitScope, 'You cannot exit global scope') if @scope_stack.size == 1
@scope_stack.pop
end
####
## Define a symbol in the current scope
# Define a symbol in the current scope
def define_symbol(symbol, value)
scope = current_scope
scope[symbol.to_sym] = value
end
####
## Separate arithmetic from scope name
# Separate arithmetic from scope name
def find_arithmetic(name)
last_name = name.split('.').last
md = last_name.match(/([\+\-\*\/])(\d+)$/)
f = lambda{|v| v}
md = last_name.match(%r{([+\-*/])(\d+)$})
f = ->(v) { v }
unless md.nil?
full_match, operator, argument = md.to_a
name.gsub!(full_match, '')
f = lambda {|value| value.send(operator.to_sym, argument.to_i) }
f = ->(value) { value.send(operator.to_sym, argument.to_i) }
end
[name, f]
end
####
## Resolve a symbol to its value
# Resolve a symbol to its value
def resolve_symbol(name)
name, arithmetic = find_arithmetic(name)
method = name.include?('.') ? :resolve_symbol_dot_syntax : :resolve_symbol_scoped
value = self.send(method, name)
value = send(method, name)
value = arithmetic.call(value)
raise(UndefinedSymbol, name) if value.nil?
fail(UndefinedSymbol, name) if value.nil?
value
end
####
## Resolve symbol by working backwards through each
## containing scope. Similarly named scopes shadow outer scopes
# Resolve symbol by working backwards through each
# containing scope. Similarly named scopes shadow outer scopes
def resolve_symbol_scoped(name)
root = "-#{name}".to_sym
stack = @scope_stack.dup
loop do
scope = retreive_scope(stack)
## We see if there is a key either under this name, or root
# We see if there is a key either under this name, or root
v = scope[name.to_sym] || scope[root]
v = v.kind_of?(Hash) ? v[root] : v
v = v.is_a?(Hash) ? v[root] : v
return v unless v.nil?
## Pop the stack so we can decend to the parent scope, if any
# Pop the stack so we can decend to the parent scope, if any
stack.pop
return nil if stack.empty?
end
end
####
## Dot syntax means to check an absolute path to the symbol
## :global is ignored if it is provided as part of the path
# Dot syntax means to check an absolute path to the symbol
# :global is ignored if it is provided as part of the path
def resolve_symbol_dot_syntax(name)
path_ary = name.split('.').map(&:to_sym)
symbol = path_ary.pop
@ -131,40 +111,32 @@ module N65
scope = retreive_scope(path_ary)
## We see if there is a key either under this name, or root
# We see if there is a key either under this name, or root
v = scope[symbol]
v.kind_of?(Hash) ? v[root] : v
v.is_a?(Hash) ? v[root] : v
end
####
## Export the symbol table as YAML
# Export the symbol table as YAML
def export_to_yaml
@symbols.to_yaml.gsub(/(\d+)$/) do |match|
integer = match.to_i
sprintf("0x%.4X", integer)
format('0x%.4X', integer)
end
end
####
## Export a cycle count for top level subroutines
# Export a cycle count for top level subroutines
def export_cycle_count_yaml
@subroutine_cycles.to_yaml
end
private
####
## A bit more clearly states to get the current scope
# A bit more clearly states to get the current scope
def current_scope
retreive_scope
end
####
## Retrieve a reference to a scope, current scope by default
# Retrieve a reference to a scope, current scope by default
def retreive_scope(path_ary = @scope_stack)
path_ary = path_ary.dup
path_ary.unshift(:global) unless path_ary.first == :global
@ -175,28 +147,22 @@ module N65
if new_scope.nil?
path_string = generate_scope_path(path_ary)
message = "Resolving scope: #{path_string} failed at #{path_component}"
fail(InvalidScope, message) if new_scope.nil?
raise(InvalidScope, message) if new_scope.nil?
end
new_scope
end
end
####
## Generate a scope path from an array
# Generate a scope path from an array
def generate_scope_path(path_ary)
path_ary.join('.')
end
####
## Generate an anonymous scope name
# Generate an anonymous scope name
def generate_name
@anonymous_scope_number += 1
"anonymous_#{@anonymous_scope_number}"
end
end
end