forked from kscience/kmath
150 lines
5.1 KiB
Markdown
150 lines
5.1 KiB
Markdown
# Module kmath-ast
|
|
|
|
Abstract syntax tree expression representation and related optimizations.
|
|
|
|
- [expression-language](src/jvmMain/kotlin/space/kscience/kmath/ast/parser.kt) : Expression language and its parser
|
|
- [mst](src/commonMain/kotlin/space/kscience/kmath/ast/MST.kt) : MST (Mathematical Syntax Tree) as expression language's syntax intermediate representation
|
|
- [mst-building](src/commonMain/kotlin/space/kscience/kmath/ast/MstAlgebra.kt) : MST building algebraic structure
|
|
- [mst-interpreter](src/commonMain/kotlin/space/kscience/kmath/ast/MST.kt) : MST interpreter
|
|
- [mst-jvm-codegen](src/jvmMain/kotlin/space/kscience/kmath/asm/asm.kt) : Dynamic MST to JVM bytecode compiler
|
|
- [mst-js-codegen](src/jsMain/kotlin/space/kscience/kmath/estree/estree.kt) : Dynamic MST to JS compiler
|
|
|
|
|
|
## Artifact:
|
|
|
|
The Maven coordinates of this project are `space.kscience:kmath-ast:0.3.0-dev-6`.
|
|
|
|
**Gradle:**
|
|
```gradle
|
|
repositories {
|
|
maven { url 'https://repo.kotlin.link' }
|
|
maven { url 'https://dl.bintray.com/hotkeytlt/maven' }
|
|
maven { url "https://dl.bintray.com/kotlin/kotlin-eap" } // include for builds based on kotlin-eap
|
|
}
|
|
|
|
dependencies {
|
|
implementation 'space.kscience:kmath-ast:0.3.0-dev-6'
|
|
}
|
|
```
|
|
**Gradle Kotlin DSL:**
|
|
```kotlin
|
|
repositories {
|
|
maven("https://repo.kotlin.link")
|
|
maven("https://dl.bintray.com/kotlin/kotlin-eap") // include for builds based on kotlin-eap
|
|
maven("https://dl.bintray.com/hotkeytlt/maven") // required for a
|
|
}
|
|
|
|
dependencies {
|
|
implementation("space.kscience:kmath-ast:0.3.0-dev-6")
|
|
}
|
|
```
|
|
|
|
## 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:
|
|
|
|
```kotlin
|
|
DoubleField.mstInField { symbol("x") + 2 }.compile()
|
|
```
|
|
|
|
… leads to generation of bytecode, which can be decompiled to the following Java class:
|
|
|
|
```java
|
|
package space.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:
|
|
|
|
```kotlin
|
|
DoubleField.mstInField { symbol("x") + 2 }.compile()
|
|
DoubleField.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.
|
|
|
|
```kotlin
|
|
DoubleField.mstInField { symbol("x") + 2 }.compile()
|
|
```
|
|
|
|
The code above returns expression implemented with such a JS function:
|
|
|
|
```js
|
|
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.
|
|
|
|
## Rendering expressions
|
|
|
|
kmath-ast also includes an extensible engine to display expressions in LaTeX or MathML syntax.
|
|
|
|
Example usage:
|
|
|
|
```kotlin
|
|
import space.kscience.kmath.ast.*
|
|
import space.kscience.kmath.ast.rendering.*
|
|
|
|
public fun main() {
|
|
val mst = "exp(sqrt(x))-asin(2*x)/(2e10+x^3)/(-12)".parseMath()
|
|
val syntax = FeaturedMathRendererWithPostProcess.Default.render(mst)
|
|
val latex = LatexSyntaxRenderer.renderWithStringBuilder(syntax)
|
|
println("LaTeX:")
|
|
println(latex)
|
|
println()
|
|
val mathML = MathMLSyntaxRenderer.renderWithStringBuilder(syntax)
|
|
println("MathML:")
|
|
println(mathML)
|
|
}
|
|
```
|
|
|
|
Result LaTeX:
|
|
|
|
%7D%7B2%5Ctimes10%5E%7B10%7D%2Bx%5E%7B3%7D%7D%7D%7B-12%7D)
|
|
|
|
Result MathML (embedding MathML is not allowed by GitHub Markdown):
|
|
|
|
```html
|
|
<mrow><msup><mrow><mi>e</mi></mrow><mrow><msqrt><mi>x</mi></msqrt></mrow></msup><mo>-</mo><mfrac><mrow><mfrac><mrow><msup><mrow><mo>sin</mo></mrow><mrow><mo>-</mo><mn>1</mn></mrow></msup><mspace width="0.167em"></mspace><mfenced open="(" close=")" separators=""><mn>2</mn><mspace width="0.167em"></mspace><mi>x</mi></mfenced></mrow><mrow><mn>2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>10</mn></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></mfrac></mrow><mrow><mo>-</mo><mn>12</mn></mrow></mfrac></mrow>
|
|
```
|
|
|
|
It is also possible to create custom algorithms of render, and even add support of other markup languages
|
|
(see API reference).
|