Package gnu.expr

Class Expression

java.lang.Object

gnu.mapping.PropertySet

gnu.mapping.Procedure

gnu.expr.Expression

All Implemented Interfaces:

gnu.kawa.format.Printable, Named, SourceLocator, SourceLocator, Locator

Direct Known Subclasses:

AccessExp, ApplyExp, BeginExp, BlockExp, CaseExp, ErrorExp, ExitExp, IfExp, LangExp, QuoteExp, ScopeExp, SynchronizedExp, TryExp

public abstract class Expression
extends Procedure
implements gnu.kawa.format.Printable, SourceLocator

Abstract class for syntactic forms that evaluate to a value. Scheme S-expressions get re-written to these before evaluation.

Nested Class Summary

Nested classes/interfaces inherited from interface gnu.text.SourceLocator

SourceLocator.Simple

Field Summary

Fields

Modifier and Type	Field	Description
static final MethodHandle	applyMethodExpression
protected int	flags
protected static final int	NEXT_AVAIL_FLAG
static final Expression[]	noExpressions
protected Type	type
static final int	VALIDATED

Fields inherited from class gnu.mapping.Procedure

applyMethodType, applyToConsumerDefault, applyToConsumerMethod, applyToObjectDefault, applyToObjectMethod, compilerKey, compilerXKey, inlineIfConstantSymbol, validateApplyKey, validateXApplyKey

Fields inherited from class gnu.mapping.PropertySet

nameKey

Constructor Summary

Constructors

Constructor	Description
Expression()

Method Summary

Modifier and Type	Method	Description
void	apply(CallContext ctx)	Evaluate the expression.
static Object	applyMethodExpression(Procedure proc, CallContext ctx)
protected Type	calculateType()
Keyword	checkLiteralKeyword()	Is this a keyword argument? In the future this will return non-null only for explicit literal non-quoted Keywords.
final void	compile(Compilation comp, Type type)
final void	compile(Compilation comp, Declaration lhs)	Compile an expression with checking suitable for a known Declaration.
abstract void	compile(Compilation comp, Target target)
final void	compileWithPosition(Compilation comp, Target target)	Same as compile, but emit line number beforehard.
final void	compileWithPosition(Compilation comp, Target target, Expression position)	Same as 2-argument compileWithPosition, but use some other Expression's line number.
protected static Expression	deepCopy(Expression exp)
static Expression[]	deepCopy(Expression[] exps, IdentityHashTable mapper)
static Expression	deepCopy(Expression exp, IdentityHashTable mapper)	Make a deep copy of this expression, if possible.
protected Expression	deepCopy(IdentityHashTable mapper)
final Object	eval(CallContext ctx)
final Object	eval(Environment env)
final int	getColumnNumber()	Return current column number.
final int	getEndColumn()	Column (one-origin) of end of range; unknown/unspecified is -1.
final int	getEndLine()	Line number (one-origin) of end of range; unknown/unspecified is -1.
final String	getFileName()	Normally same as getSystemId.
boolean	getFlag(int flag)
int	getFlags()
final int	getLineNumber()	Return current line number.
String	getPublicId()
final int	getStartColumn()	Column (one-origin) of start of range; unknown/unspecified is -1.
final int	getStartLine()	Line number (one-origin) of start of range; unknown/unspecified is -1.
String	getSystemId()
final Type	getType()	Return the Type used to represent the values of this Expression.
final Type	getTypeRaw()
boolean	isSingleValue()
boolean	isStableSourceLocation()	True if position is unlikely to change.
static Expression	makeWhile(Object cond, Object body, Compilation parser)	Helper method to create a `while' statement.
final Expression	maybeSetLine(Expression old)
protected abstract boolean	mustCompile()
boolean	neverReturns()	True if the expression provably never returns.
int	numArgs()	Return minArgs()|(maxArgs<<12).
abstract void	print(gnu.kawa.io.OutPort ps)
final void	print(Consumer out)
void	printLineColumn(gnu.kawa.io.OutPort out)	Print line and column number if specified.
final void	setFile(String filename)
void	setFlag(boolean setting, int flag)
void	setFlag(int flag)
final void	setLine(int lineno)
final void	setLine(int lineno, int colno)
final void	setLine(int startLine, int startColumn, int endLine, int endColumn)
void	setLine(Compilation comp)	Set line number from current position in Compilation.
final Expression	setLine(Expression old)
final void	setLocation(SourceLocator location)	Copies the current location.
void	setType(Type type)
boolean	side_effects()	True if evaluating may have side-effects.
String	toString()
Expression	validateApply(ApplyExp exp, InlineCalls visitor, Type required, Declaration decl)	Apply inlining transformations on a given ApplyExp.
Object	valueIfConstant()	Return value if it is constant, or null if non-constant or unknown.
protected <R, D> R	visit(ExpVisitor<R,D> visitor, D d)
protected <R, D> void	visitChildren(ExpVisitor<R,D> visitor, D d)

Methods inherited from class gnu.mapping.Procedure

apply0, apply1, apply2, apply3, apply4, applyL, applyN, applyToConsumerDefault, applyToObjectDefault, checkArgCount, checkBadCode, getApplyMethod, getApplyToConsumerMethod, getApplyToObjectMethod, getReturnType, getSetter, getSourceLocation, isSideEffectFree, lookupApplyHandle, maxArgs, maxArgs, minArgs, minArgs, set0, set1, setN, setSetter, setSourceLocation

Methods inherited from class gnu.mapping.PropertySet

getName, getProperty, getSymbol, removeProperty, setName, setProperty, setProperty, setSymbol

Methods inherited from class java.lang.Object

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

Field Details

applyMethodExpression

public static final MethodHandle applyMethodExpression

noExpressions

public static final Expression[] noExpressions

type

protected Type type

flags

protected int flags

VALIDATED

public static final int VALIDATED

See Also:

• Constant Field Values

NEXT_AVAIL_FLAG

protected static final int NEXT_AVAIL_FLAG

See Also:

• Constant Field Values

Constructor Details

Expression

public Expression()

Method Details

applyMethodExpression

public static Object applyMethodExpression(Procedure proc,
 CallContext ctx)
                                    throws Throwable

Throws:

Throwable

eval

public final Object eval(CallContext ctx)
                  throws Throwable

Throws:

Throwable

eval

public final Object eval(Environment env)
                  throws Throwable

Throws:

Throwable

mustCompile

protected abstract boolean mustCompile()

numArgs

public int numArgs()

Description copied from class: Procedure

Return minArgs()|(maxArgs<<12). We use a single virtual function to reduce the number of methods in the system, as well as the number of virtual method table entries. We shift by 12 so the number can normally be represented using a sipush instruction, without requiring a constant pool entry.

Overrides:

numArgs in class Procedure

apply

public void apply(CallContext ctx)
           throws Throwable

Evaluate the expression. This is named apply rather than eval so it is compatible with the full-tail-call calling convention, and we can stash an Expression in CallContext's proc field. FIXME - are we making use of this?

Throws:

Throwable

print

public final void print(Consumer out)

Specified by:

print in interface gnu.kawa.format.Printable

print

public abstract void print(gnu.kawa.io.OutPort ps)

printLineColumn

public void printLineColumn(gnu.kawa.io.OutPort out)

Print line and column number if specified. This is a helper routine intended for use by print(OutPort).

compile

public abstract void compile(Compilation comp,
 Target target)

compileWithPosition

public final void compileWithPosition(Compilation comp,
 Target target)

Same as compile, but emit line number beforehard.

compileWithPosition

public final void compileWithPosition(Compilation comp,
 Target target,
 Expression position)

Same as 2-argument compileWithPosition, but use some other Expression's line number.

compile

public final void compile(Compilation comp,
 Type type)

compile

public final void compile(Compilation comp,
 Declaration lhs)

Compile an expression with checking suitable for a known Declaration. Leaves the result on the stack (i.e. does not assign to the lhs). It does coerce the value to a suitable type for the lhs, and throw a hopefully-informative WrongType exception on failure.

deepCopy

public static Expression deepCopy(Expression exp,
 IdentityHashTable mapper)

Make a deep copy of this expression, if possible.

Parameters:

mapper - used to lookup parts (expressions, declarations) that have been translated in the parent. Needed for copied Declarations and BlockExps.

Returns:

a copy, or null if we can't copy.

deepCopy

public static Expression[] deepCopy(Expression[] exps,
 IdentityHashTable mapper)

deepCopy

protected static Expression deepCopy(Expression exp)

deepCopy

protected Expression deepCopy(IdentityHashTable mapper)

visit

protected <R,
D> R visit(ExpVisitor<R,D> visitor,
 D d)

visitChildren

protected <R,
D> void visitChildren(ExpVisitor<R,D> visitor,
 D d)

validateApply

public Expression validateApply(ApplyExp exp,
 InlineCalls visitor,
 Type required,
 Declaration decl)

Apply inlining transformations on a given ApplyExp. Assumes the ApplyExp's function is this expression, or can be optimized to this expression.

Parameters:

exp - an application whose function expression can be simplified to this expression.

visitor - the context for the current inlining pass

decl - if non-null, a Declaration bound to this expression.

Returns:

an Expression equivalent to the passed-in exp.

makeWhile

public static Expression makeWhile(Object cond,
 Object body,
 Compilation parser)

Helper method to create a `while' statement.

setLocation

public final void setLocation(SourceLocator location)

Copies the current location.

setLine

public final Expression setLine(Expression old)

maybeSetLine

public final Expression maybeSetLine(Expression old)

setFile

public final void setFile(String filename)

setLine

public final void setLine(int startLine,
 int startColumn,
 int endLine,
 int endColumn)

setLine

public final void setLine(int lineno,
 int colno)

setLine

public final void setLine(int lineno)

getFileName

public final String getFileName()

Description copied from interface: SourceLocator

Normally same as getSystemId.

Specified by:

getFileName in interface SourceLocator

setLine

public void setLine(Compilation comp)

Set line number from current position in Compilation.

getPublicId

public String getPublicId()

Specified by:

getPublicId in interface Locator

Specified by:

getPublicId in interface SourceLocator

Specified by:

getPublicId in interface SourceLocator

getSystemId

public String getSystemId()

Specified by:

getSystemId in interface Locator

Specified by:

getSystemId in interface SourceLocator

Specified by:

getSystemId in interface SourceLocator

getLineNumber

public final int getLineNumber()

Description copied from interface: SourceLocator

Return current line number. Normally the same as getStartLine(). The "first" line is line 1; unknown is -1.

Specified by:

getLineNumber in interface Locator

Specified by:

getLineNumber in interface SourceLocator

Specified by:

getLineNumber in interface SourceLocator

getColumnNumber

public final int getColumnNumber()

Description copied from interface: SourceLocator

Return current column number. Normally the same as getStartColumn(). The "first" column is column 1; unknown is -1.

Specified by:

getColumnNumber in interface Locator

Specified by:

getColumnNumber in interface SourceLocator

Specified by:

getColumnNumber in interface SourceLocator

getStartLine

public final int getStartLine()

Description copied from interface: SourceLocator

Line number (one-origin) of start of range; unknown/unspecified is -1.

Specified by:

getStartLine in interface SourceLocator

getStartColumn

public final int getStartColumn()

Description copied from interface: SourceLocator

Column (one-origin) of start of range; unknown/unspecified is -1.

Specified by:

getStartColumn in interface SourceLocator

getEndLine

public final int getEndLine()

Description copied from interface: SourceLocator

Line number (one-origin) of end of range; unknown/unspecified is -1.

Specified by:

getEndLine in interface SourceLocator

getEndColumn

public final int getEndColumn()

Description copied from interface: SourceLocator

Column (one-origin) of end of range; unknown/unspecified is -1.

Specified by:

getEndColumn in interface SourceLocator

isStableSourceLocation

public boolean isStableSourceLocation()

Description copied from interface: SourceLocator

True if position is unlikely to change. True for an expression but not an input file.

Specified by:

isStableSourceLocation in interface SourceLocator

getType

public final Type getType()

Return the Type used to represent the values of this Expression.

calculateType

protected Type calculateType()

getTypeRaw

public final Type getTypeRaw()

setType

public void setType(Type type)

neverReturns

public boolean neverReturns()

True if the expression provably never returns. Currently, this is very limited, not handling infinite recursion (tail- or otherwise), but better analysis is planned.

checkLiteralKeyword

public Keyword checkLiteralKeyword()

Is this a keyword argument? In the future this will return non-null only for explicit literal non-quoted Keywords.

isSingleValue

public boolean isSingleValue()

valueIfConstant

public Object valueIfConstant()

Return value if it is constant, or null if non-constant or unknown.

setFlag

public void setFlag(boolean setting,
 int flag)

setFlag

public void setFlag(int flag)

getFlags

public int getFlags()

getFlag

public boolean getFlag(int flag)

side_effects

public boolean side_effects()

True if evaluating may have side-effects.

toString

public String toString()

Overrides:

toString in class Procedure