FEngine | Unreal Engine 5.7 Documentation

API > API/Plugins > API/Plugins/OptimusCore

Simple, fast expression evaluation engine. Can evaluate simple arithmetic expressions, including user-settable constants. 1 + 1 foo + (3.0 * bar)

Allowable operands are taken from Python and are currently as follow: -x Unary negation x + y Addition x - y Subtraction x * y Multiplication x / y Division (div-by-zero returns zero) x ** y Raise x to y's power x // y Division and rounding down.

Terms can also be grouped by parentheses '(' and ')'.

Constants that begin with a number, include spaces or any of the above operands/parentheses are allowed, but must be then enclosed in single quotes when referenced. E.g: 'foo(1)' * 2.0 rather than: foo (1) * 2.0


Name	FEngine
Type	class
Header File	/Engine/Plugins/Animation/DeformerGraph/Source/OptimusCore/Public/OptimusExpressionEvaluator.h
Include Path	#include "OptimusExpressionEvaluator.h"

Syntax

class FEngine

Structs

Name	Remarks
FFunctionInfo
FTokenParseResult

Typedefs

Name	Type	Remarks	Include Path
FToken	TVariant< EOperatorToken, FName, float >		OptimusExpressionEvaluator.h
FunctionType	TFunction< float(TArrayView< const float >)>		OptimusExpressionEvaluator.h

Functions

Public

Name	Remarks	Include Path
TOptional< float > Evaluate ( FStringView InExpression, TFunctionRef< TOptional< float >(FName InConstantName)> InConstantEvaluator ) const	Evaluate an expression directly and returns the result.	OptimusExpressionEvaluator.h
float Execute ( const FExpressionObject& InExpressionObject, TFunctionRef< TOptional< float >(FName InConstantName)> InConstantEvaluator ) const	Executes the given expression object.	OptimusExpressionEvaluator.h
FParseResult Parse ( FStringView InExpression, TFunction< TOptional< float >(FName InConstantName)> InConstantEvaluator ) const	Parse an expression and either receive an error or a expression execution object that matches this evaluator.	OptimusExpressionEvaluator.h
TOptional< FParseError > Verify ( FStringView InExpression, TFunction< TOptional< float >(FName InConstantName)> InConstantEvaluator ) const	Verify an expression.	OptimusExpressionEvaluator.h

Static

Name	Remarks	Include Path
static FTokenParseResult ParseFloat ( FStringView& InOutParseRange, FStringView InExpression )	Parse a floating point value and return the result (or error).	OptimusExpressionEvaluator.h
static FTokenParseResult ParseIdentifier ( FStringView& InOutParseRange, FStringView InExpression )	Parse a constant reference and return the result (or error).	OptimusExpressionEvaluator.h
static FTokenParseResult ParseToken ( FStringView& InOutParseRange, FStringView InExpression )	Parse a single token from the beginning of the range, returning either the token or an error, if one was encountered.	OptimusExpressionEvaluator.h
static FString TokenToString ( const FToken& InToken )	Helper function to get a text version of a token.	OptimusExpressionEvaluator.h