Interface Evaluator
- All Known Subinterfaces:
StackEvaluator
,StandardEvaluator
- All Known Implementing Classes:
AbstractEvaluator
,AbstractStackEvaluator
,AbstractStandardStackEvaluator
,DefaultEvaluator
- Author:
- Curtis Rueden
-
Method Summary
Modifier and TypeMethodDescriptionEvaluates the given infix expression, returning the result.evaluate
(LinkedList<Object> queue) Evaluates the given postfix token queue, returning the result.evaluate
(SyntaxTree syntaxTree) Evaluates the given syntax tree, returning the result.Gets the value of the given variable.Gets the parser used when evaluating expressions.boolean
isStrict()
Gets whether the evaluator is operating in strict mode.void
Sets the value of the given variable.void
Assigns variables en masse.void
setStrict
(boolean strict) Sets whether the evaluator is operating in strict mode.Gets the value of the given token.
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Method Details
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getParser
ExpressionParser getParser()Gets the parser used when evaluating expressions. -
isStrict
boolean isStrict()Gets whether the evaluator is operating in strict mode.- See Also:
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setStrict
void setStrict(boolean strict) Sets whether the evaluator is operating in strict mode. Evaluators operate in strict mode by default.When evaluating strictly, usage of an unassigned variable token in a place where its value is needed will generate an
IllegalArgumentException
with an "Unknown variable" message; in non-strict mode, such a variable will instead be resolved to an object of typeUnresolved
with the same name as the original variable.In cases such as assignment, this may be sufficient to complete the evaluation; for example, the expression
foo=bar
will complete successfully in non-strict mode, with the variablefoo
containing an object of typeUnresolved
and token value"bar"
. But in cases where the unresolved value is needed as an input for additional operations, the evaluation may still ultimately fail of the operation in question is not defined for unresolved values. For example, theDefaultEvaluator
will fail with an "Unsupported binary operator" exception when given the expressionfoo+bar
, sincefoo
andbar
are unresolved variables, and the+
operator cannot handle such objects. -
evaluate
Evaluates the given infix expression, returning the result. -
evaluate
Evaluates the given postfix token queue, returning the result. -
evaluate
Evaluates the given syntax tree, returning the result. -
value
Gets the value of the given token. For variables, returns the value of the variable, throwing an exception if the variable is not set. For literals, returns the token itself. -
get
Gets the value of the given variable. -
set
Sets the value of the given variable. -
setAll
Assigns variables en masse.
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