org.millscript.millscript.expr
Class CheckExpr

java.lang.Object
  org.millscript.millscript.expr.Expr<CheckAction>
      org.millscript.millscript.expr.CheckExpr

public final class CheckExpr
extends Expr<CheckAction>

This class implements a check expression. A check expression is guaranteed to return one result.

See Also:

CheckAction

Constructor Summary

CheckExpr(Expr<?> e)
Creates a new check expression, to check the specified expression returns a single result.

Method Summary

CheckAction	compileIt() Compiles this expression into an action.
static Expr<?>	make(Expr<?> e) Returns an expression that is guaranteed to return a single result.
void	resolve(CompilerState state) Resolves any NameExpr in the tree so that they refer to the correct ident.

Methods inherited from class org.millscript.millscript.expr.Expr

arity, compile, isIntegerExpr, resolveList, setLineNumber, setOrigin, show, show

Methods inherited from class java.lang.Object

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

Constructor Detail

CheckExpr

public CheckExpr(Expr<?> e)

Creates a new check expression, to check the specified expression returns a single result.

Parameters:

e - the expression which must return a single result

Method Detail

make

public static Expr<?> make(Expr<?> e)

Returns an expression that is guaranteed to return a single result. This method provides some compile-time optimisation, as it avoids creating additional unnecessary objects in the expression tree. If the specified expression already returns a single result, it is simply returned, otherwise if it returns an unknown number of results, a new check expression is created.

Parameters:

e - the expression which must return a single result

Returns:

the specified expression if it already returns a single result, otherwise a new CheckExpr

compileIt

public CheckAction compileIt()

Description copied from class: Expr

Compiles this expression into an action.

Specified by:

compileIt in class Expr<CheckAction>

Returns:

the Action for this expression

See Also:

Expr.compileIt()

resolve

public void resolve(CompilerState state)

Description copied from class: Expr

Resolves any NameExpr in the tree so that they refer to the correct ident. e.g. This method is responsible for ensuring that references to a function argument in the body of a function actually refer to the correct value.

Specified by:

resolve in class Expr<CheckAction>

Parameters:

state - the compiler state we are resolving in

See Also:

Expr.resolve(org.millscript.millscript.vm.CompilerState)