elna/source/Parser.elna

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module;
from SYSTEM import TSIZE;
from MemUtils import MemZero;
from Storage import ALLOCATE, REALLOCATE;
from Lexer import LexerKind, LexerToken, lexer_current, lexer_lex;
(* Calls lexer_lex() but skips the comments. *)
proc transpiler_lex(lexer: PLexer) -> LexerToken;
var
result: LexerToken;
begin
result := lexer_lex(lexer);
while result.kind = lexerKindComment do
result := lexer_lex(lexer)
end;
return result
end;
proc parse_type_fields(lexer: PLexer) -> PAstFieldDeclaration;
var
token: LexerToken;
field_declarations: PAstFieldDeclaration;
field_count: CARDINAL;
current_field: PAstFieldDeclaration;
begin
ALLOCATE(field_declarations, TSIZE(AstFieldDeclaration));
token := transpiler_lex(lexer);
field_count := 0;
while token.kind <> lexerKindEnd do
INC(field_count);
REALLOCATE(field_declarations, TSIZE(AstFieldDeclaration) * (field_count + 1));
current_field := field_declarations;
INC(current_field , TSIZE(AstFieldDeclaration) * (field_count - 1));
token := transpiler_lex(lexer);
current_field^.field_name := token.identifierKind;
token := transpiler_lex(lexer);
current_field^.field_type := parse_type_expression(lexer);
token := transpiler_lex(lexer);
if token.kind = lexerKindSemicolon then
token := transpiler_lex(lexer)
end
end;
INC(current_field, TSIZE(AstFieldDeclaration));
MemZero(current_field, TSIZE(AstFieldDeclaration));
return field_declarations
end;
proc parse_record_type(lexer: PLexer) -> PAstTypeExpression;
var
result: PAstTypeExpression;
begin
NEW(result);
result^.kind := astTypeExpressionKindRecord;
result^.fields := parse_type_fields(lexer);
return result
end;
proc parse_pointer_type(lexer: PLexer) -> PAstTypeExpression;
var
token: LexerToken;
result: PAstTypeExpression;
begin
NEW(result);
result^.kind := astTypeExpressionKindPointer;
token := lexer_current(lexer);
if token.kind = lexerKindPointer then
token := transpiler_lex(lexer)
end;
token := lexer_current(lexer);
result^.target := parse_type_expression(lexer);
return result
end;
proc parse_array_type(lexer: PLexer) -> PAstTypeExpression;
var
token: LexerToken;
buffer: [20]CHAR;
result: PAstTypeExpression;
begin
NEW(result);
result^.kind := astTypeExpressionKindArray;
result^.length := 0;
token := lexer_current(lexer);
if token.kind = lexerKindArray then
token := transpiler_lex(lexer)
end;
if token.kind <> lexerKindOf then
token := transpiler_lex(lexer);
result^.length := token.integerKind;
token := transpiler_lex(lexer);
end;
token := transpiler_lex(lexer);
result^.base := parse_type_expression(lexer);
return result
end;
proc parse_enumeration_type(lexer: PLexer) -> PAstTypeExpression;
var
token: LexerToken;
result: PAstTypeExpression;
current_case: PIdentifier;
case_count: CARDINAL;
begin
NEW(result);
result^.kind := astTypeExpressionKindEnumeration;
case_count := 1;
ALLOCATE(result^.cases, TSIZE(Identifier) * 2);
token := transpiler_lex(lexer);
current_case := result^.cases;
current_case^ := token.identifierKind;
token := transpiler_lex(lexer);
while token.kind = lexerKindComma do
token := transpiler_lex(lexer);
INC(case_count);
REALLOCATE(result^.cases, TSIZE(Identifier) * (case_count + 1));
current_case := result^.cases;
INC(current_case, TSIZE(Identifier) * (case_count - 1));
current_case^ := token.identifierKind;
token := transpiler_lex(lexer)
end;
INC(current_case, TSIZE(Identifier));
MemZero(current_case, TSIZE(Identifier));
return result
end;
proc parse_named_type(lexer: PLexer) -> PAstTypeExpression;
var
token: LexerToken;
result: PAstTypeExpression;
begin
token := lexer_current(lexer);
NEW(result);
result^.kind := astTypeExpressionKindNamed;
result^.name := token.identifierKind;
return result
end;
proc parse_procedure_type(lexer: PLexer) -> PAstTypeExpression;
var
token: LexerToken;
result: PAstTypeExpression;
current_parameter: PPAstTypeExpression;
parameter_count: CARDINAL;
begin
parameter_count := 0;
NEW(result);
result^.kind := astTypeExpressionKindProcedure;
ALLOCATE(result^.parameters, 1);
token := transpiler_lex(lexer);
token := transpiler_lex(lexer);
while token.kind <> lexerKindRightParen do
INC(parameter_count);
REALLOCATE(result^.parameters, TSIZE(PAstTypeExpression) * (parameter_count + 1));
current_parameter := result^.parameters;
INC(current_parameter, TSIZE(PAstTypeExpression) * (parameter_count - 1));
current_parameter^ := parse_type_expression(lexer);
token := transpiler_lex(lexer);
if token.kind = lexerKindComma then
token := transpiler_lex(lexer)
end
end;
current_parameter := result^.parameters;
INC(current_parameter, TSIZE(PAstTypeExpression) * parameter_count);
current_parameter^ := nil;
return result
end;
proc parse_type_expression(lexer: PLexer) -> PAstTypeExpression;
var
token: LexerToken;
result: PAstTypeExpression;
begin
result := nil;
token := lexer_current(lexer);
if token.kind = lexerKindRecord then
result := parse_record_type(lexer)
end;
if token.kind = lexerKindLeftParen then
result := parse_enumeration_type(lexer)
end;
if (token.kind = lexerKindArray) or (token.kind = lexerKindLeftSquare) then
result := parse_array_type(lexer)
end;
if token.kind = lexerKindHat then
result := parse_pointer_type(lexer)
end;
if token.kind = lexerKindProc then
result := parse_procedure_type(lexer)
end;
if token.kind = lexerKindIdentifier then
result := parse_named_type(lexer)
end;
return result
end;
proc parse_type_declaration(lexer: PLexer) -> PAstTypeDeclaration;
var
token: LexerToken;
result: PAstTypeDeclaration;
begin
token := lexer_current(lexer);
NEW(result);
result^.identifier := token.identifierKind;
token := transpiler_lex(lexer);
token := transpiler_lex(lexer);
result^.type_expression := parse_type_expression(lexer);
token := transpiler_lex(lexer);
return result
end;
proc parse_type_part(lexer: PLexer) -> PPAstTypeDeclaration;
var
token: LexerToken;
result: PPAstTypeDeclaration;
current_declaration: PPAstTypeDeclaration;
declaration_count: CARDINAL;
begin
token := lexer_current(lexer);
ALLOCATE(result, TSIZE(PAstTypeDeclaration));
current_declaration := result;
declaration_count := 0;
if token.kind = lexerKindType then
token := transpiler_lex(lexer);
while token.kind = lexerKindIdentifier do
INC(declaration_count);
REALLOCATE(result, TSIZE(PAstTypeDeclaration) * (declaration_count + 1));
current_declaration := result;
INC(current_declaration, TSIZE(PAstTypeDeclaration) * (declaration_count - 1));
current_declaration^ := parse_type_declaration(lexer);
token := transpiler_lex(lexer)
end
end;
if declaration_count <> 0 then
INC(current_declaration, TSIZE(PAstTypeDeclaration))
end;
current_declaration^ := nil;
return result
end;
proc parse_variable_declaration(lexer: PLexer) -> PAstVariableDeclaration;
var
token: LexerToken;
result: PAstVariableDeclaration;
begin
NEW(result);
token := lexer_current(lexer);
result^.variable_name := token.identifierKind;
token := transpiler_lex(lexer);
token := transpiler_lex(lexer);
result^.variable_type := parse_type_expression(lexer);
token := transpiler_lex(lexer);
return result
end;
proc parse_variable_part(lexer: PLexer) -> PPAstVariableDeclaration;
var
token: LexerToken;
result: PPAstVariableDeclaration;
current_declaration: PPAstVariableDeclaration;
declaration_count: CARDINAL;
begin
token := lexer_current(lexer);
ALLOCATE(result, TSIZE(PAstVariableDeclaration));
current_declaration := result;
declaration_count := 0;
if token.kind = lexerKindVar then
token := transpiler_lex(lexer);
while token.kind = lexerKindIdentifier do
INC(declaration_count);
REALLOCATE(result, TSIZE(PAstVariableDeclaration) * (declaration_count + 1));
current_declaration := result;
INC(current_declaration, TSIZE(PAstVariableDeclaration) * (declaration_count - 1));
current_declaration^ := parse_variable_declaration(lexer);
token := transpiler_lex(lexer)
end
end;
if declaration_count <> 0 then
INC(current_declaration, TSIZE(PAstVariableDeclaration))
end;
current_declaration^ := nil;
return result
end;
proc parse_constant_declaration(lexer: PLexer) -> PAstConstantDeclaration;
var
token: LexerToken;
result: PAstConstantDeclaration;
begin
NEW(result);
token := lexer_current(lexer);
result^.constant_name := token.identifierKind;
token := transpiler_lex(lexer);
token := transpiler_lex(lexer);
result^.constant_value := token.integerKind;
token := transpiler_lex(lexer);
return result
end;
proc parse_constant_part(lexer: PLexer) -> PPAstConstantDeclaration;
var
token: LexerToken;
result: PPAstConstantDeclaration;
current_declaration: PPAstConstantDeclaration;
declaration_count: CARDINAL;
begin
token := lexer_current(lexer);
ALLOCATE(result, TSIZE(PAstConstantDeclaration));
current_declaration := result;
declaration_count := 0;
if token.kind = lexerKindConst then
token := transpiler_lex(lexer);
while token.kind = lexerKindIdentifier do
INC(declaration_count);
REALLOCATE(result, TSIZE(PAstConstantDeclaration) * (declaration_count + 1));
current_declaration := result;
INC(current_declaration, TSIZE(PAstConstantDeclaration) * (declaration_count - 1));
current_declaration^ := parse_constant_declaration(lexer);
token := transpiler_lex(lexer)
end
end;
if declaration_count <> 0 then
INC(current_declaration, TSIZE(PAstConstantDeclaration))
end;
current_declaration^ := nil;
return result
end;
proc parse_import_statement(lexer: PLexer) -> PAstImportStatement;
var
result: PAstImportStatement;
token: LexerToken;
symbol_count: CARDINAL;
current_symbol: PIdentifier;
begin
NEW(result);
symbol_count := 1;
token := transpiler_lex(lexer);
result^.package := token.identifierKind;
token := transpiler_lex(lexer);
ALLOCATE(result^.symbols, TSIZE(Identifier) * 2);
current_symbol := result^.symbols;
token := transpiler_lex(lexer);
current_symbol^ := token.identifierKind;
token := transpiler_lex(lexer);
while token.kind <> lexerKindSemicolon do
token := transpiler_lex(lexer);
INC(symbol_count);
REALLOCATE(result^.symbols, TSIZE(Identifier) * (symbol_count + 1));
current_symbol := result^.symbols;
INC(current_symbol, TSIZE(Identifier) * (symbol_count - 1));
current_symbol^ := token.identifierKind;
token := transpiler_lex(lexer)
end;
INC(current_symbol, TSIZE(Identifier));
MemZero(current_symbol, TSIZE(Identifier));
token := transpiler_lex(lexer);
return result
end;
proc parse_import_part(lexer: PLexer) -> PPAstImportStatement;
var
token: LexerToken;
import_statement: PPAstImportStatement;
result: PPAstImportStatement;
import_count: CARDINAL;
begin
token := lexer_current(lexer);
ALLOCATE(result, TSIZE(PAstImportStatement));
import_statement := result;
import_count := 0;
while token.kind = lexerKindFrom do
INC(import_count);
REALLOCATE(result, TSIZE(PAstImportStatement) * (import_count + 1));
import_statement := result;
INC(import_statement, TSIZE(PAstImportStatement) * (import_count - 1));
import_statement^ := parse_import_statement(lexer);
token := lexer_current(lexer)
end;
if import_count > 0 then
INC(import_statement, TSIZE(PAstImportStatement))
end;
import_statement^ := nil;
return result
end;
proc parse_literal(lexer: PLexer) -> PAstLiteral;
var
literal: PAstLiteral;
token: LexerToken;
begin
literal := nil;
token := lexer_current(lexer);
if token.kind = lexerKindInteger then
NEW(literal);
literal^.kind := astLiteralKindInteger;
literal^.integer := token.integerKind;
end;
if token.kind = lexerKindCharacter then
NEW(literal);
literal^.kind := astLiteralKindString;
literal^.string := token.stringKind;
end;
if token.kind = lexerKindNull then
NEW(literal);
literal^.kind := astLiteralKindNull;
end;
if literal <> nil then
token := transpiler_lex(lexer)
end;
return literal
end;
proc parse_factor(lexer: PLexer) -> PAstExpression;
var
next_token: LexerToken;
result: PAstExpression;
literal: PAstLiteral;
begin
result := nil;
next_token := lexer_current(lexer);
literal := parse_literal(lexer);
if (result = nil) & (literal <> nil) then
NEW(result);
result^.kind := astExpressionKindLiteral;
result^.literal := literal;
end;
if (result = nil) & (next_token.kind = lexerKindMinus) then
NEW(result);
next_token := transpiler_lex(lexer);
result^.kind := astExpressionKindUnary;
result^.unary_operator := astUnaryOperatorMinus;
result^.unary_operand := parse_factor(lexer)
end;
if (result = nil) & (next_token.kind = lexerKindTilde) then
NEW(result);
next_token := transpiler_lex(lexer);
result^.kind := astExpressionKindUnary;
result^.unary_operator := astUnaryOperatorNot;
result^.unary_operand := parse_factor(lexer)
end;
if (result = nil) & (next_token.kind = lexerKindIdentifier) then
NEW(result);
result^.kind := astExpressionKindIdentifier;
result^.identifier := next_token.identifierKind;
next_token := transpiler_lex(lexer)
end;
return result
end;
proc parse_designator(lexer: PLexer) -> PAstExpression;
var
next_token: LexerToken;
inner_expression: PAstExpression;
designator: PAstExpression;
handled: BOOLEAN;
begin
designator := parse_factor(lexer);
handled := designator <> nil;
next_token := lexer_current(lexer);
while handled do
inner_expression := designator;
handled := false;
if ~handled & (next_token.kind = lexerKindHat) then
NEW(designator);
designator^.kind := astExpressionKindDereference;
designator^.reference := inner_expression;
next_token := transpiler_lex(lexer);
handled := true
end;
if ~handled & (next_token.kind = lexerKindLeftSquare) then
NEW(designator);
next_token := transpiler_lex(lexer);
designator^.kind := astExpressionKindArrayAccess;
designator^.array := inner_expression;
designator^.index := parse_designator(lexer);
next_token := transpiler_lex(lexer);
handled := true
end;
if ~handled & (next_token.kind = lexerKindDot) then
NEW(designator);
next_token := transpiler_lex(lexer);
designator^.kind := astExpressionKindFieldAccess;
designator^.aggregate := inner_expression;
designator^.field := next_token.identifierKind;
next_token := transpiler_lex(lexer);
handled := true
end
end;
return designator
end;
end.