X-Git-Url: http://nitlanguage.org diff --git a/src/parser/xss/parser.xss b/src/parser/xss/parser.xss index e2fabc5..fb8b79f 100644 --- a/src/parser/xss/parser.xss +++ b/src/parser/xss/parser.xss @@ -17,151 +17,8 @@ $ // limitations under the License. $ template make_parser() -# State of the parser automata as stored in the parser stack. -private class State - # The internal state number - readable writable var _state: Int - - # The node stored with the state in the stack - readable writable var _nodes: nullable Object - - init(state: Int, nodes: nullable Object) - do - _state = state - _nodes = nodes - end -end - -class Parser - super TablesCapable - # Associated lexer - var _lexer: Lexer - - # Stack of pushed states and productions - var _stack: Array[State] - - # Position in the stack - var _stack_pos: Int - - # Create a new parser based on a given lexer - init(lexer: Lexer) - do - _lexer = lexer - _stack = new Array[State] - _stack_pos = -1 - build_reduce_table - end - - # Do a transition in the automata - private fun go_to(index: Int): Int - do - var state = state - var low = 1 - var high = parser_goto(index, 0) - 1 - - while low <= high do - var middle = (low + high) / 2 - var subindex = middle * 2 + 1 # +1 because parser_goto(index, 0) is the length - - var goal = parser_goto(index, subindex) - if state < goal then - high = middle - 1 - else if state > goal then - low = middle + 1 - else - return parser_goto(index, subindex+1) - end - end - - return parser_goto(index, 2) # Default value - end - - # Push someting in the state stack - private fun push(numstate: Int, list_node: nullable Object) - do - var pos = _stack_pos + 1 - _stack_pos = pos - if pos < _stack.length then - var state = _stack[pos] - state.state = numstate - state.nodes = list_node - else - _stack.push(new State(numstate, list_node)) - end - end - - # The current state - private fun state: Int - do - return _stack[_stack_pos].state - end - - # Pop something from the stack state - private fun pop: nullable Object - do - var res = _stack[_stack_pos].nodes - _stack_pos = _stack_pos -1 - return res - end - - # Build and return a full AST. - fun parse: Start - do - push(0, null) - - var lexer = _lexer - loop - var token = lexer.peek - if token isa PError then - return new Start(null, token) - end - - var state = self.state - var index = token.parser_index - var action_type = parser_action(state, 2) - var action_value = parser_action(state, 3) - - var low = 1 - var high = parser_action(state, 0) - 1 - - while low <= high do - var middle = (low + high) / 2 - var subindex = middle * 3 + 1 # +1 because parser_action(state, 0) is the length - - var goal = parser_action(state, subindex) - if index < goal then - high = middle - 1 - else if index > goal then - low = middle + 1 - else - action_type = parser_action(state, subindex+1) - action_value = parser_action(state, subindex+2) - break - end - end - - if action_type == 0 then # SHIFT - push(action_value, lexer.next) - else if action_type == 1 then # REDUCE - _reduce_table[action_value].action(self) - else if action_type == 2 then # ACCEPT - var node2 = lexer.next - assert node2 isa EOF - var node1 = pop - assert node1 isa ${/parser/prods/prod/@ename} - var node = new Start(node1, node2) - (new ComputeProdLocationVisitor).enter_visit(node) - return node - else if action_type == 3 then # ERROR - var node2 = new PParserError.init_parser_error("Syntax error: unexpected {token}.", token.location, token) - var node = new Start(null, node2) - return node - end - end - end - - var _reduce_table: Array[ReduceAction] - private fun build_reduce_table +redef class Parser + redef fun build_reduce_table do _reduce_table = new Array[ReduceAction].with_items( $ foreach {rules/rule} @@ -171,122 +28,6 @@ $ end foreach end end -redef class Prod - # Location on the first token after the start of a production - # So outside the production for epilon production - var _first_location: nullable Location - - # Location of the last token before the end of a production - # So outside the production for epilon production - var _last_location: nullable Location -end - -# Find location of production nodes -# Uses existing token locations to infer location of productions. -private class ComputeProdLocationVisitor - super Visitor - # Currenlty visited productions that need a first token - var _need_first_prods: Array[Prod] = new Array[Prod] - - # Already visited epsilon productions that waits something after them - var _need_after_epsilons: Array[Prod] = new Array[Prod] - - # Already visited epsilon production that waits something before them - var _need_before_epsilons: Array[Prod] = new Array[Prod] - - # Location of the last visited token in the current production - var _last_location: nullable Location = null - - redef fun visit(n: PNode) - do - if n isa Token then - var loc = n.location - _last_location = loc - - # Add a first token to productions that need one - if not _need_first_prods.is_empty then - for no in _need_first_prods do - no._first_location = loc - end - _need_first_prods.clear - end - - # Find location for already visited epsilon production that need one - if not _need_after_epsilons.is_empty then - for no in _need_after_epsilons do - # Epsilon production that is in the middle of a non-epsilon production - # The epsilon production has both a token before and after it - var endl = loc - var startl = no._last_location - no.location = new Location(endl.file, startl.line_end, endl.line_start, startl.column_end, endl.column_start) - end - _need_after_epsilons.clear - end - else - assert n isa Prod - _need_first_prods.add(n) - - var old_last = _last_location - _last_location = null - n.visit_all(self) - var endl = _last_location - if endl == null then _last_location = old_last - - n._last_location = endl - var startl = n._first_location - if startl != null then - # Non-epsilon production - assert endl != null - - n.location = new Location(startl.file, startl.line_start, endl.line_end, startl.column_start, endl.column_end) - - if not _need_before_epsilons.is_empty then - var loc = new Location(startl.file, startl.line_start, startl.line_start, startl.column_start, startl.column_start) - for no in _need_before_epsilons do - # Epsilon production that starts the current non-epsilon production - no.location = loc - end - _need_before_epsilons.clear - end - - if not _need_after_epsilons.is_empty then - var loc = new Location(endl.file, endl.line_end, endl.line_end, endl.column_end, endl.column_end) - for no in _need_after_epsilons do - # Epsilon production that finishes the current non-epsilon production - no.location = loc - end - _need_after_epsilons.clear - end - else - # No first token means epsilon production (or "throw all my tokens" production) - # So, it must be located it later - if endl == null then - # Epsilon production that starts a parent non-epsilon production - _need_before_epsilons.add(n) - else - # Epsilon production in the middle or that finishes a parent non-epsilon production - _need_after_epsilons.add(n) - end - end - end - end - - init do end -end - -# Each reduca action has its own class, this one is the root of the hierarchy. -private abstract class ReduceAction - fun action(p: Parser) is abstract - fun concat(l1, l2 : Array[Object]): Array[Object] - do - if l1.is_empty then return l2 - l1.append(l2) - return l1 - end - var _goto: Int - init(g: Int) do _goto = g -end - $ foreach {rules/rule} private class ReduceAction@index super ReduceAction