feat(jenny): Added the <<set>> command (#2155)

The <<set>> command is used to modify existing variables.

packages/flame_jenny/jenny/lib/src/parse/parse.dart

@@ -18,7 +18,6 @@ import 'package:jenny/src/structure/expressions/literal.dart';
 import 'package:jenny/src/structure/expressions/logical.dart';
 import 'package:jenny/src/structure/expressions/relational.dart';
 import 'package:jenny/src/structure/expressions/string.dart';
-import 'package:jenny/src/structure/expressions/variables.dart';
 import 'package:jenny/src/structure/node.dart';
 import 'package:jenny/src/structure/option.dart';
 import 'package:jenny/src/structure/statement.dart';
@@ -435,50 +434,40 @@ class _Parser {
  Command parseCommandSet() {
  take(Token.startCommand);
  take(Token.commandSet);
+ take(Token.startExpression);
  final variableToken = peekToken();
- if (variableToken.isVariable) {
- position += 1;
- } else {
+ if (!variableToken.isVariable) {
  syntaxError('variable expected');
  }
  final variableName = variableToken.content;
- final variableExists = project.variables.hasVariable(variableName);
+ if (!project.variables.hasVariable(variableName)) {
+ nameError('variable $variableName has not been declared');
+ }
+ position += 1;
  final assignmentToken = peekToken();
- if (assignmentTokens.contains(assignmentToken)) {
- position += 1;
- } else {
+ if (!assignmentTokens.containsKey(assignmentToken)) {
  syntaxError('an assignment operator is expected');
  }
+ position += 1;
+ final expressionStartPosition = position;
  final expression = parseExpression();
- if (variableExists) {
- final variableType = project.variables.getVariableType(variableName);
- if (variableType != expression.type) {
- typeError(
- 'variable $variableName of type ${variableType.name} cannot be '
- 'assigned a value of type ${expression.type.name}',
- );
- }
- } else {
- final variableType = expression.type;
- final dynamic initialValue = variableType is String
- ? ''
- : variableType is num
- ? 0
- : variableType is bool
- ? false
- : null;
- project.variables.setVariable(variableName, initialValue);
- assert(project.variables.getVariableType(variableName) == variableType);
- }
- if (assignmentToken != Token.operatorAssign) {
- if (!variableExists) {
- nameError('variable $variableName was not defined');
- }
- throw UnimplementedError();
+ final variableType = project.variables.getVariableType(variableName);
+ if (variableType != expression.type) {
+ position = expressionStartPosition;
+ typeError(
+ 'variable $variableName of type ${variableType.name} cannot be '
+ 'assigned a value of type ${expression.type.name}',
+ );
  }
+ final assignmentExpression = assignmentTokens[assignmentToken]!(
+ project.variables.getVariableAsExpression(variableName),
+ expression,
+ expressionStartPosition,
+ );
+ take(Token.endExpression);
  take(Token.endCommand);
  take(Token.newline);
- return SetCommand(variableName, expression);
+ return SetCommand(variableName, assignmentExpression);
  }
 
  Command parseCommandDeclare() {
@@ -534,14 +523,15 @@ class _Parser {
  throw UnimplementedError('user-defined commands are not supported yet');
  }
 
- static const List<Token> assignmentTokens = [
- Token.operatorAssign,
- Token.operatorDivideAssign,
- Token.operatorMinusAssign,
- Token.operatorModuloAssign,
- Token.operatorMultiplyAssign,
- Token.operatorPlusAssign,
- ];
+ late Map<Token, Expression Function(Expression, Expression, int)>
+ assignmentTokens = {
+ Token.operatorAssign: (lhs, rhs, pos) => rhs,
+ Token.operatorDivideAssign: _divide,
+ Token.operatorMinusAssign: _subtract,
+ Token.operatorModuloAssign: _modulo,
+ Token.operatorMultiplyAssign: _multiply,
+ Token.operatorPlusAssign: _add,
+ };
 
  //#endregion
 
@@ -627,15 +617,7 @@ class _Parser {
  } else if (token.isVariable) {
  final name = token.content;
  if (project.variables.hasVariable(name)) {
- final dynamic variable = project.variables.getVariable(name);
- if (variable is num) {
- return NumericVariable(name, project.variables);
- } else if (variable is String) {
- return StringVariable(name, project.variables);
- } else {
- assert(variable is bool);
- return BooleanVariable(name, project.variables);
- }
+ return project.variables.getVariableAsExpression(name);
  } else {
  position -= 1;
  nameError('variable $name is not defined');

packages/flame_jenny/jenny/lib/src/variable_storage.dart

@@ -1,5 +1,7 @@
 import 'package:jenny/src/errors.dart';
+import 'package:jenny/src/structure/expressions/expression.dart';
 import 'package:jenny/src/structure/expressions/expression_type.dart';
+import 'package:jenny/src/structure/expressions/variables.dart';
 import 'package:meta/meta.dart';
 
 class VariableStorage {
@@ -17,6 +19,18 @@ class VariableStorage {
  bool hasVariable(String name) => variables.containsKey(name);
  dynamic getVariable(String name) => variables[name]!;
 
+ Expression getVariableAsExpression(String name) {
+ final dynamic value = variables[name];
+ if (value is String) {
+ return StringVariable(name, this);
+ }
+ if (value is num) {
+ return NumericVariable(name, this);
+ }
+ assert(value is bool);
+ return BooleanVariable(name, this);
+ }
+
  ExpressionType getVariableType(String name) {
  final dynamic value = variables[name];
  return value is String

packages/flame_jenny/jenny/test/structure/commands/set_command_test.dart

@@ -1,9 +1,29 @@
+import 'package:jenny/jenny.dart';
+import 'package:jenny/src/parse/token.dart';
+import 'package:jenny/src/parse/tokenize.dart';
 import 'package:test/test.dart';
 
+import '../../parse/utils.dart';
 import '../../test_scenario.dart';
 
 void main() {
  group('SetCommand', () {
+ test('tokenize <<set>>', () {
+ expect(
+ tokenize(r'<<set $x = 3>>'),
+ const [
+ Token.startCommand,
+ Token.commandSet,
+ Token.startExpression,
+ Token.variable(r'$x'),
+ Token.operatorAssign,
+ Token.number('3'),
+ Token.endExpression,
+ Token.endCommand,
+ ],
+ );
+ });
+
  testScenario(
  testName: 'AnalysisTest.plan',
  input: r'''
@@ -20,12 +40,13 @@ void main() {
  ===
  ''',
  testPlan: 'line: 1 1',
- skip: true,
  );
 
  testScenario(
  testName: 'Basic.plan',
  input: r'''
+ <<declare $foo as Number>>
+ ---
  title: Start
  ---
  whoa what here's some text
@@ -40,7 +61,7 @@ void main() {
  <<else>>
  oh noooo it didn't work :(
  <<endif>>
- 
+
  <<if $foo is 54>>
  haha nice now 'set' works even when deeply nested
  <<else>>
@@ -54,7 +75,115 @@ void main() {
  line: NESTED IF BLOCK WHAAAT
  line: haha nice now 'set' works even when deeply nested
  ''',
- skip: true,
  );
+
+ testScenario(
+ testName: 'modifying assignments',
+ input: r'''
+ <<declare $x = 0>>
+ <<declare $s = 'Hello'>>
+ ---
+ title: Start
+ ---
+ <<set $x += 12>>
+ $x = {$x}
+ <<set $x *= 4>>
+ $x = {$x}
+ <<set $x /= 6>>
+ $x = {$x}
+ <<set $x %= 5>>
+ $x = {$x}
+ <<set $x -= 2>>
+ $x = {$x}
+ <<set $s += " world">>
+ $s = '{$s}'
+ ===
+ ''',
+ testPlan: r'''
+ line: $x = 12
+ line: $x = 48
+ line: $x = 8.0
+ line: $x = 3.0
+ line: $x = 1.0
+ line: $s = 'Hello world'
+ ''',
+ );
+
+ group('errors', () {
+ test('no variable', () {
+ expect(
+ () => YarnProject()
+ ..parse(
+ 'title: W\n'
+ '---\n'
+ '<<set>>\n'
+ '===\n',
+ ),
+ hasSyntaxError(
+ 'SyntaxError: variable expected\n'
+ '> at line 3 column 6:\n'
+ '> <<set>>\n'
+ '> ^\n',
+ ),
+ );
+ });
+
+ test('undeclared variable', () {
+ expect(
+ () => YarnProject()
+ ..parse(
+ 'title:E\n'
+ '---\n'
+ '<<set \$foo = 123>>\n'
+ '===\n',
+ ),
+ hasNameError(
+ 'NameError: variable \$foo has not been declared\n'
+ '> at line 3 column 7:\n'
+ '> <<set \$foo = 123>>\n'
+ '> ^\n',
+ ),
+ );
+ });
+
+ test('no assignment', () {
+ expect(
+ () => YarnProject()
+ ..parse(
+ '<<declare \$x as Number>>\n'
+ 'title: X\n'
+ '---\n'
+ '<<set \$x as String>>\n'
+ '===\n',
+ ),
+ hasSyntaxError(
+ 'SyntaxError: an assignment operator is expected\n'
+ '> at line 4 column 10:\n'
+ '> <<set \$x as String>>\n'
+ '> ^\n',
+ ),
+ );
+ });
+
+ test('wrong type in assignment', () {
+ expect(
+ () => YarnProject()
+ ..parse(
+ '<<declare \$x as String>>\n'
+ 'title: A\n'
+ '---\n'
+ '<<set \$x = 12>>\n'
+ '===\n',
+ ),
+ hasTypeError(
+ r'TypeError: variable $x of type string cannot be assigned a '
+ 'value of type numeric\n'
+ '> at line 4 column 12:\n'
+ '> <<set \$x = 12>>\n'
+ '> ^\n',
+ ),
+ );
+ });
+ });
  });
 }