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 MethodHandle`	`applyMethodExpression`
`protected int`	`flags`
`protected static int`	`NEXT_AVAIL_FLAG`
`static Expression[]`	`noExpressions`
`protected Type`	`type`
`static 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

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
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.
`void`	`compile(Compilation comp, Type type)`
`void`	`compile(Compilation comp, Declaration lhs)`	Compile an expression with checking suitable for a known Declaration.
`abstract void`	`compile(Compilation comp, Target target)`
`void`	`compileWithPosition(Compilation comp, Target target)`	Same as compile, but emit line number beforehard.
`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)`
`Object`	`eval(CallContext ctx)`
`Object`	`eval(Environment env)`
`int`	`getColumnNumber()`	Return current column number.
`int`	`getEndColumn()`	Column (one-origin) of end of range; unknown/unspecified is -1.
`int`	`getEndLine()`	Line number (one-origin) of end of range; unknown/unspecified is -1.
`String`	`getFileName()`	Normally same as getSystemId.
`boolean`	`getFlag(int flag)`
`int`	`getFlags()`
`int`	`getLineNumber()`	Return current line number.
`String`	`getPublicId()`
`int`	`getStartColumn()`	Column (one-origin) of start of range; unknown/unspecified is -1.
`int`	`getStartLine()`	Line number (one-origin) of start of range; unknown/unspecified is -1.
`String`	`getSystemId()`
`Type`	`getType()`	Return the Type used to represent the values of this Expression.
`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.
`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)`
`void`	`print(Consumer out)`
`void`	`printLineColumn(gnu.kawa.io.OutPort out)`	Print line and column number if specified.
`void`	`setFile(String filename)`
`void`	`setFlag(boolean setting, int flag)`
`void`	`setFlag(int flag)`
`void`	`setLine(int lineno)`
`void`	`setLine(int lineno, int colno)`
`void`	`setLine(int startLine, int startColumn, int endLine, int endColumn)`
`void`	`setLine(Compilation comp)`	Set line number from current position in `Compilation`.
`Expression`	`setLine(Expression old)`
`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 Detail
  - 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 Detail
  - Expression
```
public Expression()
```
- Method Detail
  - 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

Class Expression

Nested Class Summary

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

Field Summary

Fields inherited from class gnu.mapping.Procedure

Fields inherited from class gnu.mapping.PropertySet

Constructor Summary

Method Summary

Methods inherited from class gnu.mapping.Procedure

Methods inherited from class gnu.mapping.PropertySet

Methods inherited from class java.lang.Object

Field Detail

applyMethodExpression

noExpressions

type

flags

VALIDATED

NEXT_AVAIL_FLAG

Constructor Detail

Expression

Method Detail

applyMethodExpression

eval

eval

mustCompile

numArgs

apply

print

print

printLineColumn

compile

compileWithPosition

compileWithPosition

compile

compile

deepCopy

deepCopy

deepCopy

deepCopy

visit

visitChildren

validateApply

makeWhile

setLocation

setLine

maybeSetLine

setFile

setLine

setLine

setLine

getFileName

setLine

getPublicId

getSystemId

getLineNumber

getColumnNumber

getStartLine

getStartColumn

getEndLine

getEndColumn

isStableSourceLocation

getType

calculateType

getTypeRaw

setType

neverReturns

checkLiteralKeyword

isSingleValue

valueIfConstant

setFlag

setFlag

getFlags

getFlag

side_effects

toString