Package tech.ixor.calclox

Class Interpreter

java.lang.Object

tech.ixor.calclox.Interpreter

All Implemented Interfaces:

Expr.Visitor<Object>, Statement.Visitor<Void>

public class Interpreter
extends Object
implements Expr.Visitor<Object>, Statement.Visitor<Void>

Executes resolved CalcLox syntax trees against lexical environments.

The interpreter owns the globals for one run, installs the native clock and eval functions, forwards output to a CalculatorFrontend, and synchronizes numeric declarations and assignments with the frontend variable map. Instances are stateful and are not intended to be shared between runs.

Field Summary

Fields

Modifier and Type	Field	Description
final Environment	globals	Global environment containing native functions and top-level declarations.

Constructor Summary

Constructors

Constructor	Description
Interpreter(CalculatorFrontend calculatorFrontend)	Creates an interpreter connected to a host frontend.

Method Summary

Modifier and Type	Method	Description
void	executeBlock(List<Statement> statements, Environment environment)	Executes a block in a temporary environment and restores the previous environment even when execution exits through an error or function return.
void	interpret(List<Statement> statements)	Executes statements sequentially and converts internal runtime failures to the public CalcLoxRunnerError type.
void	resolve(Expr expr, int depth)	Records the lexical distance computed for a local expression by Resolver.
Object	visitAssignExpr(Expr.Assign expr)
Object	visitBinaryExpr(Expr.Binary expr)
Void	visitBlockStatement(Statement.Block statement)
Object	visitCallExpr(Expr.Call expr)
Void	visitDefineStatement(Statement.Define statement)
Void	visitExpressionStatement(Statement.Expression statement)
Void	visitFunctionStatement(Statement.Function statement)
Object	visitGroupingExpr(Expr.Grouping expr)
Void	visitIfStatement(Statement.If statement)
Object	visitLiteralExpr(Expr.Literal expr)
Object	visitLogicalExpr(Expr.Logical expr)
Void	visitOutputStatement(Statement.Output statement)
Void	visitReturnStatement(Statement.Return statement)
Object	visitUnaryExpr(Expr.Unary expr)
Object	visitVariableExpr(Expr.Variable expr)
Void	visitVarStatement(Statement.Var statement)
Void	visitWhileStatement(Statement.While statement)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

globals

public final Environment globals

Global environment containing native functions and top-level declarations.

Constructor Details

Interpreter

public Interpreter(CalculatorFrontend calculatorFrontend)

Creates an interpreter connected to a host frontend.

Parameters:

calculatorFrontend - frontend that supplies variables and receives output

Method Details

interpret

public void interpret(List<Statement> statements)

Executes statements sequentially and converts internal runtime failures to the public CalcLoxRunnerError type.

Parameters:

statements - resolved statements to execute

resolve

public void resolve(Expr expr,
 int depth)

Records the lexical distance computed for a local expression by Resolver.

Parameters:

expr - local variable expression

depth - number of enclosing environments between the expression and declaration

executeBlock

public void executeBlock(List<Statement> statements,
 Environment environment)

Executes a block in a temporary environment and restores the previous environment even when execution exits through an error or function return.

Parameters:

statements - block body

environment - lexical environment for the block

visitAssignExpr

public Object visitAssignExpr(Expr.Assign expr)

Specified by:

visitAssignExpr in interface Expr.Visitor<Object>

visitBinaryExpr

public Object visitBinaryExpr(Expr.Binary expr)

Specified by:

visitBinaryExpr in interface Expr.Visitor<Object>

visitCallExpr

public Object visitCallExpr(Expr.Call expr)

Specified by:

visitCallExpr in interface Expr.Visitor<Object>

visitGroupingExpr

public Object visitGroupingExpr(Expr.Grouping expr)

Specified by:

visitGroupingExpr in interface Expr.Visitor<Object>

visitLiteralExpr

public Object visitLiteralExpr(Expr.Literal expr)

Specified by:

visitLiteralExpr in interface Expr.Visitor<Object>

visitLogicalExpr

public Object visitLogicalExpr(Expr.Logical expr)

Specified by:

visitLogicalExpr in interface Expr.Visitor<Object>

visitUnaryExpr

public Object visitUnaryExpr(Expr.Unary expr)

Specified by:

visitUnaryExpr in interface Expr.Visitor<Object>

visitVariableExpr

public Object visitVariableExpr(Expr.Variable expr)

Specified by:

visitVariableExpr in interface Expr.Visitor<Object>

visitBlockStatement

public Void visitBlockStatement(Statement.Block statement)

Specified by:

visitBlockStatement in interface Statement.Visitor<Void>

visitDefineStatement

public Void visitDefineStatement(Statement.Define statement)

Specified by:

visitDefineStatement in interface Statement.Visitor<Void>

visitExpressionStatement

public Void visitExpressionStatement(Statement.Expression statement)

Specified by:

visitExpressionStatement in interface Statement.Visitor<Void>

visitFunctionStatement

public Void visitFunctionStatement(Statement.Function statement)

Specified by:

visitFunctionStatement in interface Statement.Visitor<Void>

visitIfStatement

public Void visitIfStatement(Statement.If statement)

Specified by:

visitIfStatement in interface Statement.Visitor<Void>

visitOutputStatement

public Void visitOutputStatement(Statement.Output statement)

Specified by:

visitOutputStatement in interface Statement.Visitor<Void>

visitReturnStatement

public Void visitReturnStatement(Statement.Return statement)

Specified by:

visitReturnStatement in interface Statement.Visitor<Void>

visitVarStatement

public Void visitVarStatement(Statement.Var statement)

Specified by:

visitVarStatement in interface Statement.Visitor<Void>

visitWhileStatement

public Void visitWhileStatement(Statement.While statement)

Specified by:

visitWhileStatement in interface Statement.Visitor<Void>