WIP: keep getting more and more of Expression parsing working with the new CST/AST node setup

Author: fractaledmind

lib/plume.rb

@@ -11,6 +11,7 @@ module Plume
 	autoload :Token, "plume/ast/token"
 
 	autoload :BinaryExpression, "plume/ast/binary_expression"
+	autoload :ParentheticalExpression, "plume/ast/parenthetical_expression"
 	autoload :Blob, "plume/ast/blob"
 	autoload :CaseCondition, "plume/ast/case_condition"
 	autoload :CaseExpression, "plume/ast/case_expression"
@@ -81,6 +82,7 @@ module Plume
 	autoload :UnionCompoundOperator, "plume/ast/union_compound_operator"
 	autoload :UniqueColumnConstraint, "plume/ast/unique_column_constraint"
 	autoload :UniqueTableConstraint, "plume/ast/unique_table_constraint"
+	autoload :LiteralExpression, "plume/ast/literal_expression"
 	autoload :Variable, "plume/ast/variable"
 	autoload :WithoutRowidTableOption, "plume/ast/without_rowid_table_option"
 

lib/plume/ast/binary_expression.rb

@@ -61,8 +61,8 @@ def after_initialize()
 			end
 		end
 
-		def operator = @operator || TOKEN_TO_OPERATOR[operator_tk_tok]
-		def left = @left || left_tk_val
-		def right = @right || right_tk_val
+		def operator = (@operator == LiteralNil) ? TOKEN_TO_OPERATOR[operator_tk_tok] : @operator
+		def left = (@left == LiteralNil) ? left_tk_val : @left
+		def right = (@right == LiteralNil) ? right_tk_val : @right
 	end
 end

lib/plume/ast/column_name.rb

@@ -15,8 +15,8 @@ class ColumnName < Node
 		def self.new(*, column:, **) = super
 		def self.concrete(*, column_tk:, **) = super
 
-		def schema = @schema || schema_tk_val
-		def table = @table || table_tk_val
-		def column = @column || column_tk_val
+		def schema = (@schema == LiteralNil) ? schema_tk_val : @schema
+		def table = (@table == LiteralNil) ? table_tk_val : @table
+		def column = (@column == LiteralNil) ? column_tk_val : @column
 	end
 end

lib/plume/ast/expression.rb

@@ -18,6 +18,7 @@ module Plume
 				RaiseExpression,
 				FunctionReference,
 				SignedExpression,
+				LiteralExpression,
 			)
 		},
 	)

lib/plume/ast/literal_expression.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module Plume
+	class LiteralExpression < Node
+		token :value_tk          # required
+
+		attr :value, _Void # required
+
+		def self.new(*, value:, **) = super
+		def self.concrete(*, **) = super
+
+		# Parser may pass either tokens or attributes, so
+		# require none in `concrete` signature but ensure presence here.
+		def after_initialize()
+			if @value == LiteralNil && @value_tk == LiteralNil
+				raise ArgumentError.new("missing either: :value, :value_tk")
+			end
+		end
+
+		def value
+			v = (@value == LiteralNil) ? value_tk_val : @value
+			case v
+			when LiteralNil then nil
+			when LiteralFalse then false
+			else v
+			end
+		end
+	end
+end

lib/plume/ast/literal_false.rb

@@ -2,4 +2,6 @@
 
 module Plume
 	LiteralFalse = Object.new
+	def LiteralFalse.inspect = "<LiteralFalse>"
+	LiteralFalse.freeze
 end

lib/plume/ast/literal_nil.rb

@@ -2,4 +2,6 @@
 
 module Plume
 	LiteralNil = Object.new
+	def LiteralNil.inspect = "<LiteralNil>"
+	LiteralNil.freeze
 end

lib/plume/ast/node.rb

@@ -43,12 +43,12 @@ def self.concrete(*, full_source:, **)
 		end
 
 		def self.attr(name, type, **kw)
-			prop name, _Nilable(type), reader: false, **kw
+			prop name, _Union(type, LiteralNil, nil), reader: false, default: LiteralNil, **kw
 			inspectable name
 		end
 
 		def self.token(name, **kw)
-			prop name, _Nilable(Token), reader: false, **kw
+			prop name, _Union(Token, LiteralNil, nil), reader: false, default: LiteralNil, **kw
 
 			# Define methods for accessing token properties, like the original source text, parsed value, and location.
 			# The token reader method is simply the parsed value of the token.

lib/plume/ast/parenthetical_expression.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module Plume
+	class ParentheticalExpression < Node
+		token :value_lp
+		token :value_tk          # required
+		token :value_rp
+
+		attr :value, _Void # required
+
+		def self.new(*, value:, **) = super
+		def self.concrete(*, **) = super
+
+		# Parser may pass either tokens or attributes, so
+		# require none in `concrete` signature but ensure presence here.
+		def after_initialize()
+			if @value == LiteralNil && @value_tk == LiteralNil
+				raise ArgumentError.new("missing either: :value, :value_tk")
+			end
+		end
+
+		def value
+			v = (@value == LiteralNil) ? value_tk_val : @value
+			case v
+			when LiteralNil then nil
+			when LiteralFalse then false
+			when LiteralExpression then v.value
+			else v
+			end
+		end
+	end
+end

lib/plume/ast/token.rb

@@ -133,9 +133,9 @@ def string_literal(str, tup)
 
 		def blob_literal(str, tup)
 			src = source(str, tup)
-			bytesize = value.bytesize
+			bytesize = src.bytesize
 			# trim the leading /x'/i and trailing /'/ then decode the hexadecimal string
-			[value.byteslice(2, bytesize - 3)].pack("H*")
+			[src.byteslice(2, bytesize - 3)].pack("H*")
 		end
 
 		def identifier(str, tup)