gnu.expr
Class Expression

java.lang.Object
  gnu.mapping.Procedure
      gnu.mapping.Procedure0
          gnu.expr.Expression

All Implemented Interfaces:

Named, Printable

Direct Known Subclasses:

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

public abstract class Expression
extends Procedure0
implements Printable

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

Field Summary

protected int	flags
protected static int	NEXT_AVAIL_FLAG
static Expression[]	noExpressions

Constructor Summary

Expression()

Method Summary

void	apply(CallContext ctx) Call this Procedure using the explicit-CallContext-convention.
java.lang.Object	apply0()
abstract void	compile(Compilation comp, Target target)
void	compile(Compilation comp, Type type)
static void	compileButFirst(Expression exp, Compilation comp) Compile all but the first sub-"statement".
void	compileNotePosition(Compilation comp, Target target, Expression position) Compile, but take note of line number.
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.
java.lang.Object	eval(CallContext ctx)
java.lang.Object	eval(Environment env)
int	getColumn()
java.lang.String	getFile()
boolean	getFlag(int flag)
int	getFlags()
int	getLine() Get the line number of (the start of) this Expression.
Type	getType() Return the Type used to represent the values of this Expression.
static Expression	makeWhile(java.lang.Object cond, java.lang.Object body, Compilation parser) Helper method to create a `while' statement.
int	match0(CallContext ctx) Pass zero arguments.
abstract void	print(OutPort ps)
void	print(java.io.PrintWriter ps)
void	printLineColumn(OutPort out) Print line and column number if specified.
void	setFile(java.lang.String filename)
void	setFlag(boolean setting, int flag)
void	setFlag(int flag)
void	setLine(Compilation comp) Set line number from current position in Compilation.
Expression	setLine(Expression old)
void	setLine(int lineno)
void	setLine(int lineno, int colno)
protected Expression	walk(ExpWalker walker)
protected void	walkChildren(ExpWalker walker)

Methods inherited from class gnu.mapping.Procedure0

apply1, apply2, apply3, apply4, applyN, numArgs

Methods inherited from class gnu.mapping.Procedure

apply, check0, check1, check2, check3, check4, checkArgCount, checkN, getName, getProperty, getSetter, getSymbol, match1, match2, match3, match4, matchN, maxArgs, minArgs, name, removeProperty, set0, set1, setN, setName, setProperty, setProperty, setSetter, setSymbol, toString

Methods inherited from class java.lang.Object

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

Field Detail

noExpressions

public static final Expression[] noExpressions

flags

protected int flags

NEXT_AVAIL_FLAG

protected static final int NEXT_AVAIL_FLAG

See Also:

Constant Field Values

Constructor Detail

Expression

public Expression()

Method Detail

eval

public java.lang.Object eval(Environment env)
                      throws java.lang.Throwable

Throws:

java.lang.Throwable

match0

public final int match0(CallContext ctx)

Description copied from class: Procedure

Pass zero arguments.

Overrides:

match0 in class Procedure

Returns:

non-negative if the match succeeded, else negative.

apply0

public final java.lang.Object apply0()
                              throws java.lang.Throwable

Specified by:

apply0 in class Procedure0

Throws:

java.lang.Throwable

apply

public void apply(CallContext ctx)
           throws java.lang.Throwable

Description copied from class: Procedure

Call this Procedure using the explicit-CallContext-convention. The input arguments are (by default) in stack.args; the result is written to ctx.consumer.

Overrides:

apply in class Procedure

Throws:

java.lang.Throwable

eval

public final java.lang.Object eval(CallContext ctx)
                            throws java.lang.Throwable

Throws:

java.lang.Throwable

print

public final void print(java.io.PrintWriter ps)

Specified by:

print in interface Printable

print

public abstract void print(OutPort ps)

printLineColumn

public void printLineColumn(OutPort out)

Print line and column number if specified. This is a helper routineintended 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.

compileNotePosition

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

Compile, but take note of line number.

compile

public final void compile(Compilation comp,
                          Type type)

compileButFirst

public static void compileButFirst(Expression exp,
                                   Compilation comp)

Compile all but the first sub-"statement". A kludge used for constructor methods, since if the first "statement" is a super-constructor we need to inject initializer expressions.

walk

protected Expression walk(ExpWalker walker)

walkChildren

protected void walkChildren(ExpWalker walker)

makeWhile

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

Helper method to create a `while' statement.

setLine

public final Expression setLine(Expression old)

setFile

public final void setFile(java.lang.String filename)

setLine

public final void setLine(int lineno,
                          int colno)

setLine

public final void setLine(int lineno)

getFile

public final java.lang.String getFile()

setLine

public void setLine(Compilation comp)

Set line number from current position in Compilation.

getLine

public final int getLine()

Get the line number of (the start of) this Expression. The "first" line is line 1.

getColumn

public final int getColumn()

getType

public Type getType()

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

setFlag

public void setFlag(boolean setting,
                    int flag)

setFlag

public void setFlag(int flag)

getFlags

public int getFlags()

getFlag

public boolean getFlag(int flag)