Package fmpp.tdd

Interface EvaluationEnvironment

All Known Implementing Classes:

DataLoaderEvaluationEnvironment

public interface EvaluationEnvironment

Callbacks that let you control the behaviour of TDD expression evaluation.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	EVENT_ENTER_FUNCTION_PARAMS	The code of event that indicates that we have started to evaluate the parameter list in a function call.
static final int	EVENT_ENTER_HASH	The code of event that indicates that we have started to evaluate the items in a hash.
static final int	EVENT_ENTER_HASH_KEY	The code of event that indicates that we have started to evaluate the value in a key:value pair.
static final int	EVENT_ENTER_SEQUENCE	The code of event that indicates that we have started to evaluate the items in a sequence.
static final int	EVENT_LEAVE_FUNCTION_PARAMS	The code of event that indicates that we have finished to evaluate the parameter list in a function call.
static final int	EVENT_LEAVE_HASH	The code of event that indicates that we have finished to evaluate the items in a sequence.
static final int	EVENT_LEAVE_HASH_KEY	The code of event that indicates that we have finished to evaluate the value in a key:value pair.
static final int	EVENT_LEAVE_SEQUENCE	The code of event that indicates that we have finished to evaluate the items in a sequence.
static final Object	RETURN_FRAGMENT
static final Object	RETURN_SKIP

Method Summary

Modifier and Type	Method	Description
Object	evalFunctionCall(FunctionCall fc, Interpreter ip)	Evaluates the function call.
Object	notify(int event, Interpreter ip, String name, Object extra)	Notifies about an event during expression evaluation.

Field Details

EVENT_ENTER_HASH_KEY

static final int EVENT_ENTER_HASH_KEY

The code of event that indicates that we have started to evaluate the value in a key:value pair.

See Also:

• Constant Field Values

EVENT_LEAVE_HASH_KEY

static final int EVENT_LEAVE_HASH_KEY

The code of event that indicates that we have finished to evaluate the value in a key:value pair.

See Also:

• Constant Field Values

EVENT_ENTER_FUNCTION_PARAMS

static final int EVENT_ENTER_FUNCTION_PARAMS

The code of event that indicates that we have started to evaluate the parameter list in a function call.

See Also:

• Constant Field Values

EVENT_LEAVE_FUNCTION_PARAMS

static final int EVENT_LEAVE_FUNCTION_PARAMS

The code of event that indicates that we have finished to evaluate the parameter list in a function call.

See Also:

• Constant Field Values

EVENT_ENTER_SEQUENCE

static final int EVENT_ENTER_SEQUENCE

The code of event that indicates that we have started to evaluate the items in a sequence. This does not include function call parameter lists.

See Also:

• Constant Field Values

EVENT_LEAVE_SEQUENCE

static final int EVENT_LEAVE_SEQUENCE

The code of event that indicates that we have finished to evaluate the items in a sequence.

See Also:

• Constant Field Values

EVENT_ENTER_HASH

static final int EVENT_ENTER_HASH

The code of event that indicates that we have started to evaluate the items in a hash.

See Also:

• Constant Field Values

EVENT_LEAVE_HASH

static final int EVENT_LEAVE_HASH

The code of event that indicates that we have finished to evaluate the items in a sequence.

See Also:

• Constant Field Values

RETURN_SKIP

static final Object RETURN_SKIP

RETURN_FRAGMENT

static final Object RETURN_FRAGMENT

Method Details

evalFunctionCall

Object evalFunctionCall(FunctionCall fc,
 Interpreter ip)
                 throws Exception

Evaluates the function call. This method may simply returns its parameter, which means that the function was not resolved, and thus the function call will be availble for further interpretation in the result of the TDD expression evaluation.

Parameters:

fc - the function call to evaluate.

Returns:

the return value of the function call. During the evaluation of a TDD expression, function calls will be replaced with their return values. If the return value is a FunctionCall object, it will not be evaluated again. This way, the final result of a TDD expression evaluation can contain FunctionCall objects.

Throws:

Exception

notify

Object notify(int event,
 Interpreter ip,
 String name,
 Object extra)
       throws Exception

Notifies about an event during expression evaluation.

Parameters:

event - An EVENT_... constant. Further events may will be added later, so the implementation must silently ignore events that it does not know. It is guaranteed that for each EVENT_ENTER_... event there will be an EVENT_LEAVE_... event later, except if notifyContextChange has thrown exception during handling EVENT_ENTER_..., in which case it is guaranteed that there will be no corresponding EVENT_LEAVE_... event.

ip - the Interpreter instance that evaluates the text. The value returned by Interpreter.getPosition() will be the position in the text where the this even has been created:

• EVENT_ENTER_HASH_KEY: points the first character of the value of the key:value pair.
• EVENT_ENTER_SEQUENCE, EVENT_ENTER_HASH, and EVENT_ENTER_FUNCTION_PARAMS: points the first character after the [ and ( respectively.
• EVENT_LEAVE_SEQUENCE, EVENT_LEAVE_HASH, and EVENT_LEAVE_FUNCTION_PARAMS: points the terminating character, that is, the ] or ) or the character after the end of the string.

name - For EVENT_ENTER_HASH_KEY and EVENT_ENTER_FUNCTION_PARAMS, the name of the hash key or function. It is null otherwise.

extra - Even specific extra information.

• For EVENT_ENTER_HASH, EVENT_LEAVE_HASH, EVENT_ENTER_SEQUENCE, EVENT_LEAVE_SEQUENCE it is the Map or List that is being built by the hash or sequence. It's OK to modify this Map or List.
• For other events it's value is currently null.

Returns:

return The allowed return values and their meaning depends on the event. But return value null always means "do nothing special". The currently defiend non-null return values for the events:

• EVENT_ENTER_HASH_KEY:
  • RETURN_SKIP: Skip the key:value pair. That is, the key:value pair will not be added to the map. The value expression will not be evaluated.
  • RETURN_FRAGMENT: The value of the key:value pair will be the Fragment that stores the value expression. The value expression will not be evaluated. However, if the value is implicit boolean true, (i.e. you omit the value) then RETURN_FRAGMENT has no effect.
• EVENT_ENTER_HASH if the hash uses { and }):
  • RETURN_FRAGMENT: The value of the hash will be the Fragment that stores the hash expression. The hash expression will not be evaluated.

Throws:

Exception