forked from kscience/kmath
2.1 KiB
2.1 KiB
Abstract Syntax Tree Expression Representation and Operations (kmath-ast
)
This subproject implements the following features:
${features}
${artifact}
Dynamic expression code generation
On JVM
kmath-ast
JVM module supports runtime code generation to eliminate overhead of tree traversal. Code generator builds
a special implementation of Expression<T>
with implemented invoke
function.
For example, the following builder:
RealField.mstInField { symbol("x") + 2 }.compile()
… leads to generation of bytecode, which can be decompiled to the following Java class:
package kscience.kmath.asm.generated;
import java.util.Map;
import kotlin.jvm.functions.Function2;
import space.kscience.kmath.asm.internal.MapIntrinsics;
import space.kscience.kmath.expressions.Expression;
import space.kscience.kmath.expressions.Symbol;
public final class AsmCompiledExpression_45045_0 implements Expression<Double> {
private final Object[] constants;
public final Double invoke(Map<Symbol, ? extends Double> arguments) {
return (Double)((Function2)this.constants[0]).invoke((Double)MapIntrinsics.getOrFail(arguments, "x"), 2);
}
public AsmCompiledExpression_45045_0(Object[] constants) {
this.constants = constants;
}
}
Example Usage
This API extends MST and MstExpression, so you may optimize as both of them:
RealField.mstInField { symbol("x") + 2 }.compile()
RealField.expression("x+2".parseMath())
Known issues
- The same classes may be generated and loaded twice, so it is recommended to cache compiled expressions to avoid class loading overhead.
- This API is not supported by non-dynamic JVM implementations (like TeaVM and GraalVM) because of using class loaders.
On JS
A similar feature is also available on JS.
RealField.mstInField { symbol("x") + 2 }.compile()
The code above returns expression implemented with such a JS function:
var executable = function (constants, arguments) {
return constants[1](constants[0](arguments, "x"), 2);
};
Known issues
- This feature uses
eval
which can be unavailable in several environments.