modelverse/interface/HUTN/hutn_compiler/semantics_visitor.py

import hutn_compiler.hutnparser as hp
import hutn_compiler.symbol_table as st
import sys
from hutn_compiler.declare_functions_visitor import DeclareFunctionsVisitor
from hutn_compiler.hutnparser import Tree
from hutn_compiler.visitor import Visitor

class SemanticsVisitor(Visitor):
    def __init__(self, args):
        Visitor.__init__(self, args)
        self.symbol_table = st.SymbolTable()

        # there is only one input file, list is for sharing it among visitors
        self.inputfiles = []

        # Count whether we are in a while or not
        self.while_counter = 0

        # inherited attribute, set in funcdecl and used in return,
        # to ensure that (returned type == declared type)
        self.current_funcdecl = None

        self.declare_functions_visitor = DeclareFunctionsVisitor(self.symbol_table, self.inputfiles)

    @staticmethod
    def incompatible_types(l_type, r_type):
        if type(l_type) != type(r_type):
            if "Void" in (type(l_type), type(r_type)):
                return True
            if "Element" in (type(l_type), type(r_type)):
                return False
            if l_type not in ["Integer", "Float", "Boolean"] or r_type not in ["Integer", "Float", "Boolean"]:
                return True
        return False

    def do_check_binary_ops_arithmetic(self, l, r):
        l_type, r_type = self.get_type(l), self.get_type(r)
        if SemanticsVisitor.incompatible_types(l_type, r_type):
            raise RuntimeError(
                "{}:{}:{}: error: invalid operands to binary operator "
                "(have {} and {})".format(self.inputfiles[0],
                                          l['startpos'][0],
                                          l['startpos'][1],
                                          str(l_type),
                                          str(r_type)))

    def check_binary_ops_arithmetic(self, tree):
        l, r = Tree.get_tail(tree)[0], Tree.get_tail(tree)[2]
        self.do_check_binary_ops_arithmetic(l, r)

    def generalize_binary_ops_arithmetic(self, tree):
        l, r = Tree.get_tail(tree)[0], Tree.get_tail(tree)[2]
        l_type, r_type = self.get_type(l), self.get_type(r)
        if l_type == "Float" or r_type == "Float":
            return "Float"
        elif l_type == "Integer" or r_type == "Integer":
            return "Integer"
        else:
            return "Boolean"

    def check_unary_ops_arithmetic(self, tree, operator_name):
        l = Tree.get_tail(tree)[1]
        l_type = self.get_type(l)
        if l_type not in ["Boolean", "Integer", "Float"]:
            raise RuntimeError(
                "{}:{}:{}: error: wrong type argument to unary {} "
                "({})".format(self.inputfiles[0],
                              l['startpos'][0],
                              l['startpos'][1],
                              operator_name,
                              str(l_type)))

    def promote_unary_ops_arithmetic(self, tree):
        l = Tree.get_tail(tree)[1]
        l_type = self.get_type(l)
        try:
            if l_type == "Boolean":
                return "Integer"
            elif l_type == "Integer" or l_type == "Float":
                return l_type
            else:
                raise RuntimeError("You cannot promote {} to a numeric type".format(str(l_type)))
        except RuntimeError:
            raise RuntimeError(
                "Pathological situation in promote_unary_ops_arithmetic: "
                "check_unary_ops_arithmetic has not been executed")

    # if r_type is provided, r is not used
    def do_check_assignment(self, l, r, r_type = None):
        if r_type is not None:
            l_type = self.get_type(l)
        else:
            l_type, r_type = self.get_type(l), self.get_type(r)
        if SemanticsVisitor.incompatible_types(l_type, r_type):
            raise RuntimeError("{}:{}:{}: error: cannot assign a value of "
                               "type '{}' to a variable of type '{}'"
                .format(self.inputfiles[0],
                        l['startpos'][0],
                        l['startpos'][1],
                        str(r_type),
                        str(l_type)))

    def check_assignment(self, tree):
        l, r = Tree.get_tail(tree)[0], Tree.get_tail(tree)[2]
        self.do_check_assignment(l, r)

    def check_return(self, tree):
        l = self.current_funcdecl

        if len(Tree.get_tail(tree)) > 2:
            r = Tree.get_tail(tree)[1]
            r_type = None
        else:
            r = None
            r_type = "Void"

        if l:
            self.do_check_assignment(l, r, r_type)
        else:
            raise RuntimeError(
                "{}:{}:{}: error: 'return' is used outside of a function"
                .format(self.inputfiles[0],
                        tree['startpos'][0],
                        tree['startpos'][1]))

    def check_predicate(self, tree):
        if self.get_type(tree) == "Element":
            return
        if self.get_type(tree) not in ["Boolean", "Integer", "Float"]:
            raise RuntimeError(
                "{}:{}:{}: error: predicates of type '{}' are not allowed"
                .format(self.inputfiles[0],
                        tree['startpos'][0],
                        tree['startpos'][1],
                        self.get_type(tree)))

    def replace_child_binary_op_with_call(self, tree, i=0):
        if i == -1:
            child = tree
        else:
            child = Tree.get_tail(tree)[i]
        if len(Tree.get_tail(child)) > 1:
            try:
                l, op, r = Tree.get_tail(child)
            except:
                # Something went wrong... this code is severely broken
                return
            l_type, r_type = self.get_type(l), self.get_type(r)
            if type(l_type) != type(r_type):
                print("Error: " + str(l_type) + " <-> " + str(r_type))
                raise RuntimeError(
                    "{}:{}:{}: error: children were not casted".format(
                        self.inputfiles[0],
                        tree['startpos'][0],
                        tree['startpos'][1]
                    ))
            call_name = SemanticsVisitor.call_name_binary(l_type, op)
            call_tree = self.func_call(call_name, [l, r], tree)
            try:
                self.visit(call_tree)
            except RuntimeError:
                print(call_name)
                print(l_type)
                call_signature = "Boolean function {1}({2}, {2})".format(call_name, l_type)
                raise RuntimeError(
                    "{}:{}:{}: error: cannot perform {}: function '{}' is "
                    "not found".format(
                        self.inputfiles[0],
                        tree['startpos'][0],
                        tree['startpos'][1],
                        child['head'],
                        call_signature))
            if i == -1:
                tree['head'] = call_tree['head']
                tree['tail'] = call_tree['tail']
                tree['_tail'] = None
            else:
                Tree.replace_child(tree, child, call_tree)
        self.set_type(tree, self.get_type(Tree.get_tail(tree)[i]))

    def replace_child_unary_op_with_call(self, tree):
        child = Tree.get_tail(tree)[0]
        if child['head'] == "keep_sign":
            Tree.replace_child(tree, child, Tree.get_tail(child)[1])
        else:
            op, l = Tree.get_tail(child)
            l_type = self.get_type(l)
            call_name = SemanticsVisitor.call_name_unary(l_type, op)
            call_tree = self.func_call(call_name, [l], tree)
            try:
                self.visit(call_tree)
            except RuntimeError:
                call_signature = "Boolean function {1}({2})".format(call_name, l_type)
                raise RuntimeError(
                    "{}:{}:{}: error: cannot perform {}: function '{}' is "
                    "not found".format(
                        self.inputfiles[0],
                        tree['startpos'][0],
                        tree['startpos'][1],
                        child['head'],
                        call_signature))
            Tree.replace_child(tree, child, call_tree)
        self.set_type(tree, self.get_type(Tree.get_tail(tree)[0]))

    def cast_binary_ops_arithmetic(self, tree):
        l, op, r = Tree.get_tail(tree)
        l_type, r_type = self.get_type(l), self.get_type(r)
        if type(l_type) != type(r_type):  # if two different numeric types
            if l_type == "Float" or r_type == "Float":
                g_type = "Float"
            elif l_type == "Integer" or r_type == "Integer":
                g_type = "Integer"
            else:
                g_type = "Boolean"
            self.perform_implicit_cast(tree, l, l_type, g_type)
            self.perform_implicit_cast(tree, r, r_type, g_type)

    def cast_binary_ops_logical(self, tree):
        l, op, r = Tree.get_tail(tree)
        l_type, r_type = self.get_type(l), self.get_type(r)
        self.perform_implicit_cast(tree, l, l_type, "Boolean")
        self.perform_implicit_cast(tree, r, r_type, "Boolean")

    def cast_unary_ops_arithmetic(self, tree):
        l = Tree.get_tail(tree)[1]
        l_type = self.get_type(l)
        p_type = self.promote_unary_ops_arithmetic(tree)
        self.perform_implicit_cast(tree, l, l_type, p_type)

    def func_call(self, name, params, old_tree):
        startpos = old_tree['startpos']
        endpos = old_tree['endpos']
        inputfile = old_tree['inputfile']

        tree = {"head": "func_call",
                "tail": [
                    {"head": "rvalue",
                     "tail": [
                        {"head": "ID",
                         "tail": [name],
                         "startpos": startpos,
                         "endpos": endpos,
                         "inputfile": inputfile}],
                     "startpos": startpos,
                     "endpos": endpos,
                     "inputfile": inputfile}],
                "startpos": startpos,
                "endpos": endpos,
                "inputfile": inputfile}

        for p in params:
            self.replace_child_binary_op_with_call(p, -1)

        params = [{"head": "expression", "tail": [p], "startpos": startpos, "endpos": endpos, "inputfile": inputfile} for p in params]

        tree['tail'].extend(params)

        return {"head": "expression", "tail": [tree], "startpos": startpos, "endpos": endpos, "inputfile": inputfile}

    @staticmethod
    def cast_name(from_type, to_type):
        to_t = str(to_type)[0].lower()
        cast_name = "cast_" + {"f": "float", "i": "integer", "b": "boolean", "s": "string"}[to_t]
        return cast_name

    def raise_implicit_cast_error(self, from_type, to_type, tree):
        cast_name = SemanticsVisitor.cast_name(from_type, to_type)
        cast_signature = "{} function {}({})".format(
            str(to_type), cast_name, str(from_type))
        raise RuntimeError(
            "{}:{}:{}: error: cannot perform implicit cast from '{}'"
            " to '{}': function '{}' is not found".format(
                self.inputfiles[0],
                tree['startpos'][0],
                tree['startpos'][1],
                str(to_type), str(from_type),
                cast_signature))

    def perform_implicit_cast(self, tree, child, from_type, to_type):
        if "Element" in (from_type, to_type):
            return
        if from_type == to_type:
            return
        cast_name = SemanticsVisitor.cast_name(from_type, to_type)
        cast_tree = self.func_call(cast_name, [child], tree)
        try:
            self.visit(cast_tree)
        except RuntimeError:
            self.raise_implicit_cast_error(from_type, to_type, child)
        Tree.replace_child(tree, child, cast_tree)

    types = {
        "Integer": "integer",
        "Float": "float",
        "Boolean": "bool",
        "String": "string",
        "Action": "action",
        "Element": "element",
        "Type": "type"
    }

    binary_ops = {
        "OR": "or",
        "AND": "and",
        "EQ": "eq",
        "NEQ": "neq",
        "LT": "lt",
        "GT": "gt",
        "LE": "lte",
        "GE": "gte",
        "PLUS": "addition",
        "MINUS": "subtraction",
        "STAR": "multiplication",
        "SLASH": "division"
    }

    unary_ops = {
        "NOT": "not",
        "MINUS": "neg"
    }

    @staticmethod
    def call_name_binary(operand_type, operator):
        # String joins should also be possible
        if str(operand_type) == "String":
            if operator['head'] == "PLUS":
                return "string_join"

        if operator['head'] == "EQ":
            return "value_eq"
        elif operator['head'] == "NEQ":
            return "value_neq"

        call_name = "{}_{}".format(SemanticsVisitor.types[str(operand_type)],
                                   SemanticsVisitor.binary_ops[operator['head']])
        return call_name

    @staticmethod
    def call_name_unary(operand_type, operator):
        call_name = "{}_{}".format(SemanticsVisitor.types[str(operand_type)],
                                   SemanticsVisitor.unary_ops[operator['head']])

        return call_name

    def dump(self):
        return Tree.get_text(self.tree, with_implicit=True)
        # return "No code generation here"

    # a visit_* method for each non-terminal in the grammar
    def visit_start(self, tree):
        self.symbol_table.open_scope()
        self.inputfiles.append(tree['inputfile'])
        for child in Tree.get_tail(tree):
            self.inputfiles[0] = child['inputfile']
            self.declare_functions_visitor.visit(child)
        for child in Tree.get_tail(tree):
            self.inputfiles[0] = child['inputfile']
            self.visit(child)
        self.inputfiles.pop()
        self.symbol_table.close_scope()
        self.tree = tree

    def visit_statement(self, tree):
        self.visit_children(tree)

    def visit_definition(self, tree):
        self.visit_vardecl(tree)

    def visit_vardecl(self, tree):
        type_spec = Tree.get_child(tree, "type_specifier")
        var_id = Tree.get_child(tree, "ID")

        var_type = Tree.get_text(type_spec)
        var_name = Tree.get_text(var_id)

        symbol = {"name": var_name, "type": var_type, "is_global": self.current_funcdecl is None, "node": None, "params": None}

        try:
            self.symbol_table.add(symbol)
        except Exception:
            raise RuntimeError(
                "{}:{}:{}: error: redeclaration of '{}'".format(
                    self.inputfiles[0], tree['startpos'][0],
                    tree['startpos'][1], var_name))

        self.set_symbol(tree, symbol)

    def visit_assignment(self, tree):
        self.visit_children(tree)
        self.check_assignment(tree)

    def visit_expression(self, tree):
        self.visit_children(tree)
        self.set_type(tree, self.get_type(Tree.get_tail(tree)[0]))

    def visit_binary_operation(self, tree):
        self.visit_children(tree)
        self.replace_child_binary_op_with_call(tree)

    def visit_disjunction(self, tree):
        self.visit_children(tree)
        if len(Tree.get_tail(tree)) == 1:
            self.replace_child_binary_op_with_call(tree)
        else:
            self.replace_child_binary_op_with_call(tree, 2)
            self.cast_binary_ops_logical(tree)
            self.set_type(tree, "Boolean")

    def visit_conjunction(self, tree):
        self.visit_children(tree)
        if len(Tree.get_tail(tree)) == 1:
            self.replace_child_binary_op_with_call(tree)
        else:
            self.replace_child_binary_op_with_call(tree, 2)
            self.cast_binary_ops_logical(tree)
            self.set_type(tree, "Boolean")

    def visit_comparison(self, tree):
        self.visit_children(tree)
        if len(Tree.get_tail(tree)) == 1:
            self.replace_child_binary_op_with_call(tree)
        else:
            self.replace_child_binary_op_with_call(tree, 2)
            self.check_binary_ops_arithmetic(tree)
            self.cast_binary_ops_arithmetic(tree)
            self.set_type(tree, "Boolean")

    def visit_relation(self, tree):
        self.visit_children(tree)
        if len(Tree.get_tail(tree)) == 1:
            self.replace_child_binary_op_with_call(tree)
        else:
            self.replace_child_binary_op_with_call(tree, 2)
            self.check_binary_ops_arithmetic(tree)
            self.cast_binary_ops_arithmetic(tree)
            self.set_type(tree, "Boolean")

    def visit_sum(self, tree):
        self.visit_children(tree)
        if len(Tree.get_tail(tree)) == 1:
            self.replace_child_binary_op_with_call(tree)
        else:
            self.replace_child_binary_op_with_call(tree, 2)
            self.check_binary_ops_arithmetic(tree)
            self.cast_binary_ops_arithmetic(tree)
            # after the cast both parameters have the same (generalized) type:
            self.set_type(tree, self.get_type(Tree.get_tail(tree)[0]))

    def visit_term(self, tree):
        self.visit_children(tree)
        if len(Tree.get_tail(tree)) == 1:
            self.set_type(tree, self.get_type(Tree.get_tail(tree)[0]))
        else:
            self.check_binary_ops_arithmetic(tree)
            self.cast_binary_ops_arithmetic(tree)
            # after the cast both parameters have the same (generalized) type:
            self.set_type(tree, self.get_type(Tree.get_tail(tree)[0]))

    def visit_factor(self, tree):
        self.visit_children(tree)
        if Tree.get_child(tree, "primary") is not None:
            self.set_type(tree, self.get_type(Tree.get_tail(tree)[0]))
        else:
            self.replace_child_unary_op_with_call(tree)

    def visit_logical_not(self, tree):
        self.visit_children(tree)

        l = Tree.get_tail(tree)[1]
        l_type = self.get_type(l)
        self.perform_implicit_cast(tree, l, l_type, "Boolean")

        self.set_type(tree, self.get_type(Tree.get_tail(tree)[1]))

    def visit_invert_sign(self, tree):
        self.visit_children(tree)

        self.check_unary_ops_arithmetic(tree, "minus")
        self.cast_unary_ops_arithmetic(tree)

        self.set_type(tree, self.get_type(Tree.get_tail(tree)[1]))

    def visit_keep_sign(self, tree):
        self.visit_children(tree)

        self.check_unary_ops_arithmetic(tree, "plus")
        self.cast_unary_ops_arithmetic(tree)

        self.set_type(tree, self.get_type(Tree.get_tail(tree)[1]))

    def visit_primary(self, tree):
        self.visit_children(tree)
        self.set_type(tree, self.get_type(Tree.get_tail(tree)[0]))

    def visit_parenthesized(self, tree):
        self.visit_children(tree)
        self.set_type(tree, self.get_type(Tree.get_tail(tree)[1]))

    def visit_atomvalue(self, tree):
        self.visit_children(tree)
        self.set_type(tree, self.get_type(Tree.get_tail(tree)[0]))

    def visit_type_specifier(self, tree):
        self.set_type(tree, "Type")

    def visit_actionname(self, tree):
        self.set_type(tree, "Action")

    def visit_string(self, tree):
        self.set_type(tree, "String")

    def visit_integer(self, tree):
        self.set_type(tree, "Integer")

    def visit_float(self, tree):
        self.set_type(tree, "Float")

    # there is no such rule in the grammar, we just avoid code duplicates
    def visit_id(self, tree):
        name = Tree.get_text(tree)
        #TODO this is set to the function returnvalue, even if we use the function pointer...
        try:
            symbol = self.symbol_table.get(name)
        except KeyError:
            raise RuntimeError("{}:{}:{}: error: '{}' is not declared".format(
                self.inputfiles[0], tree['startpos'][0],
                tree['startpos'][1], name))
        self.set_type(tree, symbol['type'])
        self.set_symbol(tree, symbol)

    def visit_rvalue(self, tree):
        if len(Tree.get_tail(tree)) > 1:
            # Complex: dict_read operation needed
            child = Tree.get_tail(tree)[0]
            node = Tree.get_child(tree, "rvalue")
            expression = Tree.get_child(tree, "expression")
            operation = "dict_read"
            call_tree = self.func_call(operation, [node, expression], tree)
            self.visit(call_tree)
            tree['head'] = call_tree['head']
            tree['_tail'] = call_tree['tail']
            tree['tail'] = call_tree['tail']
            self.set_type(tree, self.get_type(node))
        else:
            # Simple
            self.visit_id(tree)

    def visit_lvalue(self, tree):
        self.visit_id(tree)

    def visit_func_call(self, tree):
        self.visit_children(tree)

        symbol = self.get_symbol(Tree.get_tail(tree)[0])
        self.set_type(tree, symbol['type'])

        if not st.Symbol.is_func(symbol):
            if symbol['type'] == "Element":
                return  # allow the call without knowing the declaration
            raise RuntimeError(
                "{}:{}:{}: error: '{}' is a variable of type '{}', not a "
                "function".format(self.inputfiles[0],
                                  tree['startpos'][0],
                                  tree['startpos'][1],
                                  symbol['name'],
                                  symbol['type']))

        expressions = Tree.get_children(tree, "expression")
        if len(expressions) != len(symbol['params']):
            raise RuntimeError(
                "{}:{}:{}: error: wrong number of arguments to "
                "function '{}'".format(self.inputfiles[0],
                                       tree['startpos'][0],
                                       tree['startpos'][1],
                                       st.Symbol.signature(symbol)))

        if symbol['name'] == "__input":
            tree['head'] = "input"
        elif symbol['name'] == "__output":
            tree['head'] = "output"

    def visit_input(self, tree):
        pass  # no need to visit it again

    def visit_output(self, tree):
        pass  # no need to visit it again

    def visit_dictionary(self, tree):
        self.set_type(tree, "Element")

    def visit_list(self, tree):
        self.set_type(tree, "Element")

    def visit_dict_item(self, tree):
        pass

    def visit_ifelse(self, tree):
        self.visit_children(tree)
        expressions = Tree.get_children(tree, "expression")
        for expression in expressions:
            self.check_predicate(expression)

    def visit_while(self, tree):
        self.while_counter += 1
        self.visit_children(tree)
        self.while_counter -= 1
        expression = Tree.get_child(tree, "expression")
        self.check_predicate(expression)

    def visit_block(self, tree):
        self.symbol_table.open_scope()
        self.visit_children(tree)
        self.symbol_table.close_scope()

    def visit_func_body(self, tree):
        self.visit_children(tree)

    def visit_funcdecl(self, tree):
        # here we only visit the body cause the declaration is already done
        # by declare_functions_visitor
        if Tree.get_child(tree, 'func_body') is not None:
            self.current_funcdecl = tree

            self.symbol_table.open_scope()
            self.visit_children(tree)
            self.symbol_table.close_scope()

            self.current_funcdecl = None

    def visit_parameter(self, tree):
        param_id = Tree.get_child(tree, "ID")
        type_spec = Tree.get_child(tree, "type_specifier")

        param_type = Tree.get_text(type_spec)
        param_name = Tree.get_text(param_id)

        symbol = {"name": param_name, "type": param_type, "is_global": False, "node": None, "params": None}

        try:
            self.symbol_table.add(symbol)
        except Exception:
            raise RuntimeError(
                "{}:{}:{}: error: redeclaration of '{}'".format(
                    self.inputfiles[0], tree['startpos'][0],
                    tree['startpos'][1], param_name))

        self.set_symbol(tree, symbol)

    def visit_return(self, tree):
        self.visit_children(tree)
        self.check_return(tree)

    def visit_bool(self, tree):
        self.set_type(tree, "Boolean")

    def visit_break(self, tree):
        if self.while_counter == 0:
            raise RuntimeError(
                "{}:{}:{}: error: break outside of while".format(
                    self.inputfiles[0], tree['startpos'][0],
                    tree['startpos'][1]))

    def visit_continue(self, tree):
        if self.while_counter == 0:
            raise RuntimeError(
                "{}:{}:{}: error: continue outside of while".format(
                    self.inputfiles[0], tree['startpos'][0],
                    tree['startpos'][1]))