Class: Dentaku::Parser
- Inherits:
-
Object
- Object
- Dentaku::Parser
- Defined in:
- lib/dentaku/parser.rb
Constant Summary collapse
- AST_OPERATIONS =
{ add: AST::Addition, subtract: AST::Subtraction, multiply: AST::Multiplication, divide: AST::Division, pow: AST::Exponentiation, negate: AST::Negation, mod: AST::Modulo, bitor: AST::BitwiseOr, bitand: AST::BitwiseAnd, lt: AST::LessThan, gt: AST::GreaterThan, le: AST::LessThanOrEqual, ge: AST::GreaterThanOrEqual, ne: AST::NotEqual, eq: AST::Equal, and: AST::And, or: AST::Or, }.freeze
Instance Attribute Summary collapse
-
#arities ⇒ Object
readonly
Returns the value of attribute arities.
-
#case_sensitive ⇒ Object
readonly
Returns the value of attribute case_sensitive.
-
#input ⇒ Object
readonly
Returns the value of attribute input.
-
#operations ⇒ Object
readonly
Returns the value of attribute operations.
-
#output ⇒ Object
readonly
Returns the value of attribute output.
Instance Method Summary collapse
- #consume(count = 2) ⇒ Object
- #function(token) ⇒ Object
- #function_registry ⇒ Object
-
#initialize(tokens, options = {}) ⇒ Parser
constructor
A new instance of Parser.
- #operation(token) ⇒ Object
- #parse ⇒ Object
Constructor Details
#initialize(tokens, options = {}) ⇒ Parser
Returns a new instance of Parser.
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# File 'lib/dentaku/parser.rb', line 29 def initialize(tokens, = {}) @input = tokens.dup @output = [] @operations = .fetch(:operations, []) @arities = .fetch(:arities, []) @function_registry = .fetch(:function_registry, nil) @case_sensitive = .fetch(:case_sensitive, false) end |
Instance Attribute Details
#arities ⇒ Object (readonly)
Returns the value of attribute arities.
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# File 'lib/dentaku/parser.rb', line 27 def arities @arities end |
#case_sensitive ⇒ Object (readonly)
Returns the value of attribute case_sensitive.
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# File 'lib/dentaku/parser.rb', line 27 def case_sensitive @case_sensitive end |
#input ⇒ Object (readonly)
Returns the value of attribute input.
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# File 'lib/dentaku/parser.rb', line 27 def input @input end |
#operations ⇒ Object (readonly)
Returns the value of attribute operations.
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# File 'lib/dentaku/parser.rb', line 27 def operations @operations end |
#output ⇒ Object (readonly)
Returns the value of attribute output.
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# File 'lib/dentaku/parser.rb', line 27 def output @output end |
Instance Method Details
#consume(count = 2) ⇒ Object
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# File 'lib/dentaku/parser.rb', line 38 def consume(count = 2) operator = operations.pop operator.peek(output) args_size = operator.arity || count if args_size > output.length fail! :too_few_operands, operator: operator, expect: args_size, actual: output.length end args = Array.new(args_size) { output.pop }.reverse output.push operator.new(*args) rescue ::ArgumentError => e raise Dentaku::ArgumentError, e. rescue NodeError => e fail! :node_invalid, operator: operator, child: e.child, expect: e.expect, actual: e.actual end |
#function(token) ⇒ Object
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# File 'lib/dentaku/parser.rb', line 291 def function(token) function_registry.get(token.value) end |
#function_registry ⇒ Object
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# File 'lib/dentaku/parser.rb', line 295 def function_registry @function_registry ||= Dentaku::AST::FunctionRegistry.new end |
#operation(token) ⇒ Object
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# File 'lib/dentaku/parser.rb', line 287 def operation(token) AST_OPERATIONS.fetch(token.value) end |
#parse ⇒ Object
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# File 'lib/dentaku/parser.rb', line 55 def parse return AST::Nil.new if input.empty? while token = input.shift case token.category when :datetime output.push AST::DateTime.new(token) when :numeric output.push AST::Numeric.new(token) when :logical output.push AST::Logical.new(token) when :string output.push AST::String.new(token) when :identifier output.push AST::Identifier.new(token, case_sensitive: case_sensitive) when :operator, :comparator, :combinator op_class = operation(token) if op_class.right_associative? while operations.last && operations.last < AST::Operation && op_class.precedence < operations.last.precedence consume end operations.push op_class else while operations.last && operations.last < AST::Operation && op_class.precedence <= operations.last.precedence consume end operations.push op_class end when :null output.push AST::Nil.new when :function func = function(token) if func.nil? fail! :undefined_function, function_name: token.value end arities.push 0 operations.push func when :case case_index = operations.index { |o| o == AST::Case } || -1 token_index = case_index + 1 case token.value when :open # special handling for case nesting: strip out inner case # statements and parse their AST segments recursively if operations.include?(AST::Case) open_cases = 0 case_end_index = nil input.each_with_index do |input_token, index| if input_token.category == :case if input_token.value == :open open_cases += 1 end if input_token.value == :close if open_cases > 0 open_cases -= 1 else case_end_index = index break end end end end inner_case_inputs = input.slice!(0..case_end_index) subparser = Parser.new( inner_case_inputs, operations: [AST::Case], arities: [0], function_registry: @function_registry ) subparser.parse output.concat(subparser.output) else operations.push AST::Case arities.push(0) end when :close if operations[token_index] == AST::CaseThen while operations.last != AST::Case consume end operations.push(AST::CaseConditional) consume(2) arities[-1] += 1 elsif operations[token_index] == AST::CaseElse while operations.last != AST::Case consume end arities[-1] += 1 end unless operations.count >= 1 && operations.last == AST::Case fail! :unprocessed_token, token_name: token.value end consume(arities.pop.succ) when :when if operations[token_index] == AST::CaseThen while ![AST::CaseWhen, AST::Case].include?(operations.last) consume end operations.push(AST::CaseConditional) consume(2) arities[-1] += 1 elsif operations.last == AST::Case operations.push(AST::CaseSwitchVariable) consume end operations.push(AST::CaseWhen) when :then if operations[token_index] == AST::CaseWhen while ![AST::CaseThen, AST::Case].include?(operations.last) consume end end operations.push(AST::CaseThen) when :else if operations[token_index] == AST::CaseThen while operations.last != AST::Case consume end operations.push(AST::CaseConditional) consume(2) arities[-1] += 1 end operations.push(AST::CaseElse) else fail! :unknown_case_token, token_name: token.value end when :access case token.value when :lbracket operations.push AST::Access when :rbracket while operations.any? && operations.last != AST::Access consume end unless operations.last == AST::Access fail! :unbalanced_bracket, token: token end consume end when :array case token.value when :array_start operations.push AST::Array arities.push 0 when :array_end while operations.any? && operations.last != AST::Array consume end unless operations.last == AST::Array fail! :unbalanced_bracket, token: token end consume(arities.pop.succ) end when :grouping case token.value when :open if input.first && input.first.value == :close input.shift arities.pop consume(0) else operations.push AST::Grouping end when :close while operations.any? && operations.last != AST::Grouping consume end lparen = operations.pop unless lparen == AST::Grouping fail! :unbalanced_parenthesis, token end if operations.last && operations.last < AST::Function consume(arities.pop.succ) end when :comma fail! :invalid_statement if arities.empty? arities[-1] += 1 while operations.any? && operations.last != AST::Grouping && operations.last != AST::Array consume end else fail! :unknown_grouping_token, token_name: token.value end else fail! :not_implemented_token_category, token_category: token.category end end while operations.any? consume end unless output.count == 1 fail! :invalid_statement end output.first end |