simplify coulomb's implicit type system

.github/workflows/ci.yml

@@ -80,11 +80,11 @@ jobs:
 
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/scala3')
-        run: mkdir -p runtime/.js/target spire/.js/target spire/.jvm/target testkit/.native/target units/.jvm/target runtime/.native/target testkit/.js/target parser/.jvm/target unidocs/target parser/.js/target core/.native/target pureconfig/.jvm/target spire/.native/target parser/.native/target core/.js/target units/.native/target runtime/.jvm/target core/.jvm/target refined/.native/target refined/.js/target refined/.jvm/target units/.js/target testkit/.jvm/target project/target
+        run: mkdir -p runtime/.js/target testkit/.native/target units/.jvm/target runtime/.native/target testkit/.js/target parser/.jvm/target unidocs/target parser/.js/target core/.native/target pureconfig/.jvm/target parser/.native/target core/.js/target units/.native/target runtime/.jvm/target core/.jvm/target refined/.native/target refined/.js/target refined/.jvm/target units/.js/target testkit/.jvm/target project/target
 
       - name: Compress target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/scala3')
-        run: tar cf targets.tar runtime/.js/target spire/.js/target spire/.jvm/target testkit/.native/target units/.jvm/target runtime/.native/target testkit/.js/target parser/.jvm/target unidocs/target parser/.js/target core/.native/target pureconfig/.jvm/target spire/.native/target parser/.native/target core/.js/target units/.native/target runtime/.jvm/target core/.jvm/target refined/.native/target refined/.js/target refined/.jvm/target units/.js/target testkit/.jvm/target project/target
+        run: tar cf targets.tar runtime/.js/target testkit/.native/target units/.jvm/target runtime/.native/target testkit/.js/target parser/.jvm/target unidocs/target parser/.js/target core/.native/target pureconfig/.jvm/target parser/.native/target core/.js/target units/.native/target runtime/.jvm/target core/.jvm/target refined/.native/target refined/.js/target refined/.jvm/target units/.js/target testkit/.jvm/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/scala3')

benchmarks/src/main/scala/coulomb/benchmarks/quantity.scala

@@ -20,6 +20,23 @@ import java.util.concurrent.TimeUnit
 
 import org.openjdk.jmh.annotations.*
 
+object algebras:
+    import algebra.ring.*
+    // inlining typeclass methods can be leveraged by inline code
+    // however so far, only for these "static" typeclass objects.
+    // For cases where the typeclass has to be constructed per invocation,
+    // it seems to be impossible for scala to make "full" use of the inlining,
+    // so I am not going to try to in-line methods for typeclasses that
+    // must be non-static functions of their types, for example UnitConversion
+    given DoubleIsField: Field[Double] with
+        inline def zero: Double = 0.0
+        inline def one: Double = 1.0
+        inline def plus(x: Double, y: Double): Double = x + y
+        inline def negate(x: Double): Double = -x
+        override inline def minus(x: Double, y: Double): Double = x - y
+        inline def times(x: Double, y: Double): Double = x * y
+        inline def div(x: Double, y: Double): Double = x / y
+
 @State(Scope.Thread)
 @Fork(1)
 @BenchmarkMode(Array(Mode.Throughput))
@@ -32,9 +49,6 @@ class QuantityBenchmark:
     import coulomb.syntax.*
     import coulomb.testing.units.{*, given}
     import algebra.instances.all.given
-    import coulomb.ops.algebra.all.given
-
-    import coulomb.policy.standard.given
 
     var data: Vector[Quantity[Double, Meter]] =
         Vector.empty[Quantity[Double, Meter]]
@@ -49,7 +63,7 @@ class QuantityBenchmark:
 
     @Benchmark
     def add1V1U_opt(): Quantity[Double, Meter] =
-        import coulomb.ops.standard.optimizations.all.given
+        import coulomb.benchmarks.algebras.given
         data.foldLeft(0d.withUnit[Meter]) { (s, x) => s + x }
 
     @Benchmark
@@ -58,23 +72,5 @@ class QuantityBenchmark:
 
     @Benchmark
     def add1V2U_opt(): Quantity[Double, Kilo * Meter] =
-        import coulomb.ops.standard.optimizations.all.given
+        import coulomb.benchmarks.algebras.given
         data.foldLeft(0d.withUnit[Kilo * Meter]) { (s, x) => s + x }
-
-    @Benchmark
-    def add2V1U(): Quantity[Float, Meter] =
-        data.foldLeft(0f.withUnit[Meter]) { (s, x) => s + x }
-
-    @Benchmark
-    def add2V1U_opt(): Quantity[Float, Meter] =
-        import coulomb.ops.standard.optimizations.all.given
-        data.foldLeft(0f.withUnit[Meter]) { (s, x) => s + x }
-
-    @Benchmark
-    def add2V2U(): Quantity[Float, Kilo * Meter] =
-        data.foldLeft(0f.withUnit[Kilo * Meter]) { (s, x) => s + x }
-
-    @Benchmark
-    def add2V2U_opt(): Quantity[Float, Kilo * Meter] =
-        import coulomb.ops.standard.optimizations.all.given
-        data.foldLeft(0f.withUnit[Kilo * Meter]) { (s, x) => s + x }

build.sbt

@@ -2,8 +2,9 @@
 // sbt githubWorkflowGenerate
 // and check in the updates to github workflow yamls
 
+// this line to kick off pull request from branch 'simplify-coulomb'
 // base version for assessing MIMA
-ThisBuild / tlBaseVersion := "0.8"
+ThisBuild / tlBaseVersion := "0.9"
 
 // publish settings
 // artifacts now publish to s01.oss.sonatype.org, per:
@@ -61,7 +62,6 @@ lazy val root = tlCrossRootProject
         runtime,
         parser,
         pureconfig,
-        spire,
         refined,
         testkit,
         unidocs
@@ -73,6 +73,7 @@ lazy val core = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     .settings(name := "coulomb-core")
     .settings(commonSettings: _*)
     .settings(libraryDependencies += "org.typelevel" %%% "algebra" % "2.10.0")
+    .settings(libraryDependencies += "org.typelevel" %%% "spire" % "0.18.0")
     .platformsSettings(JSPlatform, NativePlatform)(
         Test / unmanagedSources / excludeFilter := HiddenFileFilter || "*serde.scala"
     )
@@ -150,14 +151,6 @@ lazy val pureconfig = crossProject(
         libraryDependencies += "com.github.pureconfig" %%% "pureconfig-core" % "0.17.6"
     )
 
-lazy val spire = crossProject(JVMPlatform, JSPlatform, NativePlatform)
-    .crossType(CrossType.Pure)
-    .in(file("spire"))
-    .settings(name := "coulomb-spire")
-    .dependsOn(core % "compile->compile;test->test", units % Test)
-    .settings(commonSettings: _*)
-    .settings(libraryDependencies += "org.typelevel" %%% "spire" % "0.18.0")
-
 lazy val refined = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     .crossType(CrossType.Pure)
     .in(file("refined"))
@@ -195,7 +188,6 @@ lazy val all = project
         runtime.jvm,
         parser.jvm,
         pureconfig.jvm,
-        spire.jvm,
         refined.jvm
     ) // scala repl only needs JVMPlatform subproj builds
     .settings(name := "coulomb-all")
@@ -225,7 +217,6 @@ lazy val docs = project
         runtime.jvm,
         parser.jvm,
         pureconfig.jvm,
-        spire.jvm,
         refined.jvm
     )
     .enablePlugins(TypelevelSitePlugin)
@@ -248,11 +239,35 @@ lazy val docs = project
                             "https://scala-lang.org/api/3.x/"
                         ).withPackagePrefix("scala")
                     )
+                    .addApiLinks(
+                        ApiLinks(
+                            "https://javadoc.io/doc/org.typelevel/algebra_3/latest/"
+                        ).withPackagePrefix("algebra")
+                    )
+                    .addApiLinks(
+                        ApiLinks(
+                            "https://javadoc.io/doc/org.typelevel/cats-core_3/latest/"
+                        ).withPackagePrefix("cats")
+                    )
+                    .addApiLinks(
+                        ApiLinks(
+                            "https://javadoc.io/doc/org.typelevel/spire_3/latest/"
+                        ).withPackagePrefix("spire")
+                    )
                     .addApiLinks(
                         ApiLinks(
                             "https://javadoc.io/doc/com.github.pureconfig/pureconfig-core_3/latest/"
                         ).withPackagePrefix("pureconfig")
                     )
+                    .addApiLinks(
+                        // the refined api link isn't super helpful because @:api(...)
+                        // doesn't work for type defs or methods, which is most of
+                        // what refined provides
+                        ApiLinks(
+                            // refined is not publishing scaladoc for scala 3 yet
+                            "https://javadoc.io/doc/eu.timepit/refined_2.13/latest/"
+                        ).withPackagePrefix("eu.timepit.refined")
+                    )
                     .addTargets(
                         // Target names need to be all lowercase.
                         // Note, this does not align with Laika docs.
@@ -265,6 +280,10 @@ lazy val docs = project
                             "quantitytypedef",
                             "https://www.javadoc.io/doc/com.manyangled/coulomb-docs_3/latest/coulomb.html#Quantity[V,U]=V"
                         ),
+                        TargetDefinition.external(
+                            "refinedapidocs",
+                            "https://javadoc.io/doc/eu.timepit/refined_2.13/latest/eu/timepit/refined/index.html"
+                        ),
                         TargetDefinition.internal(
                             "coulomb-introduction",
                             VirtualPath.parse("README.md")
@@ -277,10 +296,6 @@ lazy val docs = project
                             "coulomb-units",
                             VirtualPath.parse("coulomb-units.md")
                         ),
-                        TargetDefinition.internal(
-                            "coulomb-spire",
-                            VirtualPath.parse("coulomb-spire.md")
-                        ),
                         TargetDefinition.internal(
                             "coulomb-refined",
                             VirtualPath.parse("coulomb-refined.md")

core/src/main/scala/coulomb/conversion/coefficient.scala

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2022 Erik Erlandson
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package coulomb.conversion
+
+import scala.annotation.implicitNotFound
+
+/**
+ * A typeclass representing a unit conversion coefficient.
+ * @tparam V
+ *   the value type the unit conversion is operating on
+ * @tparam UF
+ *   the unit being converted from
+ * @tparam UT
+ *   the unit being converted to
+ * @param value
+ *   the value of the conversion coefficient
+ */
+@implicitNotFound(
+    "No coefficient could be derived for value type ${V}, unit types ${UF} => ${UT}"
+)
+class Coefficient[V, UF, UT](val value: V)
+
+/** unit conversion companion methods and definitions */
+object Coefficient:
+    import scala.compiletime.*
+    import algebra.ring.*
+    import spire.math.*
+    import coulomb.infra.typeexpr
+    import coulomb.conversion.coefficients.*
+
+    /**
+     * Obtain the coefficient of conversion from one unit expression to another
+     * @tparam UF
+     *   the input unit expression
+     * @tparam UT
+     *   the output unit expression
+     * @tparam V
+     *   the value type to return
+     * @return
+     *   The coefficient of conversion from UF to UT.
+     * @note
+     *   If UF and UT are not convertible, or if a coefficient
+     *   cannot be constructed for value type `V`, then a
+     *   compilation failure will result.
+     */
+    inline def apply[V, UF, UT]: V =
+        inline erasedValue[V] match
+            case _: Float      => coefficientFloat[UF, UT].asInstanceOf[V]
+            case _: Double     => coefficientDouble[UF, UT].asInstanceOf[V]
+            case _: BigDecimal => coefficientBigDecimal[UF, UT].asInstanceOf[V]
+            case _: Rational   => coefficientRational[UF, UT].asInstanceOf[V]
+            case _: java.lang.Float =>
+                coefficientFloatJ[UF, UT].asInstanceOf[V]
+            case _: java.lang.Double =>
+                coefficientDoubleJ[UF, UT].asInstanceOf[V]
+            case _ =>
+                summonInline[Coefficient[V, UF, UT]].value
+
+    inline given g_Coefficient[V, UF, UT]: Coefficient[V, UF, UT] =
+        inline erasedValue[V] match
+            case _: Float =>
+                new Coefficient[V, UF, UT](
+                    coefficientFloat[UF, UT].asInstanceOf[V]
+                )
+            case _: Double =>
+                new Coefficient[V, UF, UT](
+                    coefficientDouble[UF, UT].asInstanceOf[V]
+                )
+            case _: BigDecimal =>
+                new Coefficient[V, UF, UT](
+                    coefficientBigDecimal[UF, UT].asInstanceOf[V]
+                )
+            case _: Rational =>
+                new Coefficient[V, UF, UT](
+                    coefficientRational[UF, UT].asInstanceOf[V]
+                )
+            case _: java.lang.Float =>
+                new Coefficient[V, UF, UT](
+                    coefficientFloatJ[UF, UT].asInstanceOf[V]
+                )
+            case _: java.lang.Double =>
+                new Coefficient[V, UF, UT](
+                    coefficientDoubleJ[UF, UT].asInstanceOf[V]
+                )
+            case _ =>
+                val (_, vc) =
+                    summonAll[(Fractional[V], ValueConversion[Rational, V])]
+                new Coefficient[V, UF, UT](vc(coefficientRational[UF, UT]))