Add findBindingDoc trampoline.

runtime/src/main/java/dev/ionfusion/fusion/ModuleNamespace.java

@@ -9,6 +9,7 @@
 import static dev.ionfusion.fusion.UnboundIdentifierException.makeUnboundError;
 
 import dev.ionfusion.fusion.FusionSymbol.BaseSymbol;
+import dev.ionfusion.runtime._private.doc.BindingDoc;
 import dev.ionfusion.runtime.base.FusionException;
 import dev.ionfusion.runtime.base.ModuleIdentity;
 import dev.ionfusion.runtime.base.SourceLocation;
@@ -378,6 +379,13 @@ Object lookup(ModuleInstance module)
             return store.lookup(myAddress);
         }
 
+        @Override
+        BindingDoc lookupDoc(Namespace current)
+        {
+            ModuleInstance module = current.getRegistry().lookup(myModuleId);
+            return (module == null) ? null : module.getStore().document(myAddress);
+        }
+
         @Override
         String mutationSyntaxErrorMessage()
         {

runtime/src/main/java/dev/ionfusion/fusion/ModuleStore.java

@@ -121,6 +121,10 @@ else if (value instanceof SyntacticForm)
                 {
                     doc.setKind(BindingDoc.Kind.SYNTAX);
                 }
+                else
+                {
+                    doc.setKind(BindingDoc.Kind.CONSTANT);
+                }
             }
             return doc;
         }

runtime/src/main/java/dev/ionfusion/fusion/Namespace.java

@@ -140,6 +140,8 @@ final boolean isOwnedBy(Namespace ns)
             return Namespace.this.myModuleId == ns.myModuleId;
         }
 
+        abstract BindingDoc lookupDoc(Namespace current);
+
         @Override
         public boolean equals(Object other)
         {

runtime/src/main/java/dev/ionfusion/fusion/TopLevelNamespace.java

@@ -10,6 +10,7 @@
 
 import dev.ionfusion.fusion.FusionSymbol.BaseSymbol;
 import dev.ionfusion.fusion.ModuleNamespace.ProvidedBinding;
+import dev.ionfusion.runtime._private.doc.BindingDoc;
 import dev.ionfusion.runtime.base.FusionException;
 import dev.ionfusion.runtime.base.ModuleIdentity;
 import java.util.Iterator;
@@ -68,6 +69,14 @@ public Object lookup(Namespace ns)
             return ns.lookupDefinition(this);
         }
 
+
+        @Override
+        BindingDoc lookupDoc(Namespace current)
+        {
+            assert current == TopLevelNamespace.this;  // Not always, but just testing
+            return TopLevelNamespace.this.document(myAddress);
+        }
+
         @Override
         NsDefinedBinding redefine(SyntaxSymbol identifier,
                                   SyntaxValue formForErrors)

runtime/src/main/java/dev/ionfusion/fusion/_Private_Trampoline.java

@@ -3,6 +3,8 @@
 
 package dev.ionfusion.fusion;
 
+import dev.ionfusion.fusion.Namespace.NsDefinedBinding;
+import dev.ionfusion.runtime._private.doc.BindingDoc;
 import dev.ionfusion.runtime._private.doc.ModuleDocs;
 import dev.ionfusion.runtime.base.FusionException;
 import dev.ionfusion.runtime.base.ModuleIdentity;
@@ -61,6 +63,24 @@ public static ModuleDocs instantiateModuleDocs(TopLevel top, ModuleIdentity id)
     }
 
 
+    /**
+     * @param identifier must be a syntax symbol.
+     *
+     * @return null if no documentation is available.
+     */
+    public static BindingDoc findBindingDoc(TopLevel top, Object identifier)
+    {
+        Evaluator eval    = ((StandardTopLevel) top).getEvaluator();
+        Binding   binding = ((SyntaxSymbol) identifier).resolve().target();
+        if (binding instanceof NsDefinedBinding)
+        {
+            Namespace current = eval.findCurrentNamespace();
+            return ((NsDefinedBinding) binding).lookupDoc(current);
+        }
+        return null;
+    }
+
+
     public static FusionException newFusionException(String message,
                                                      Throwable cause)
     {

runtime/src/test/fusion/modules/documentation.fusion

@@ -0,0 +1,24 @@
+// Copyright Ion Fusion contributors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+(module documentation "/fusion"
+  "This is the module body doc."
+
+  (require "/fusion/private/syntax")
+
+  (provide const proc macro)
+
+
+  (define const
+    "This is the const doc."
+    true)
+
+  (define (proc)
+    "This is the proc doc."
+    true)
+
+  (define_syntax macro
+    "This is the macro doc."
+    (lambda (stx)
+      (quote_syntax (void))))
+)

runtime/src/test/java/dev/ionfusion/fusion/DocumentationAccessTest.java

@@ -0,0 +1,125 @@
+// Copyright Ion Fusion contributors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package dev.ionfusion.fusion;
+
+import static dev.ionfusion.fusion._Private_Trampoline.findBindingDoc;
+import static dev.ionfusion.fusion._Private_Trampoline.instantiateModuleDocs;
+import static dev.ionfusion.fusion._Private_Trampoline.setDocumenting;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.is;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+
+import dev.ionfusion.runtime._private.doc.BindingDoc;
+import dev.ionfusion.runtime._private.doc.ModuleDocs;
+import dev.ionfusion.runtime.base.FusionException;
+import dev.ionfusion.runtime.base.ModuleIdentity;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class DocumentationAccessTest
+    extends CoreTestCase
+{
+    @BeforeEach
+    public void setup()
+        throws Exception
+    {
+        setDocumenting(runtimeBuilder(), true);
+        useTstRepo();
+
+        topLevel().requireModule("/fusion/private/syntax");
+        topLevel().requireModule("/documentation");
+    }
+
+
+    private ModuleDocs moduleDocs(String modulePath)
+        throws FusionException
+    {
+        ModuleIdentity modId = ModuleIdentity.forAbsolutePath(modulePath);
+
+        ModuleDocs doc = instantiateModuleDocs(topLevel(), modId);
+        if (doc != null)
+        {
+            assertSame(doc.getIdentity(), modId);
+        }
+
+        return doc;
+    }
+
+    private BindingDoc bindingDoc(String name)
+        throws FusionException
+    {
+        Object id = topLevel().eval("(quote_syntax " + name + ")");
+        return findBindingDoc(topLevel(), id);
+    }
+
+
+    @Test
+    public void docForUnknownModule()
+        throws FusionException
+    {
+        assertNull(moduleDocs("/unknown/module/path"));
+    }
+
+
+    @Test
+    public void docForModule()
+        throws FusionException
+    {
+        ModuleDocs doc = moduleDocs("/documentation");
+
+        assertThat(doc.getOneLiner(), is("This is the module body doc."));
+        assertThat(doc.getOverview(), is("This is the module body doc."));
+
+        assertThat(doc.getProvidedNames(),
+                   containsInAnyOrder("const", "macro", "proc"));
+
+
+        BindingDoc constDoc = doc.getBindingDocs().get("const");
+
+        assertThat(constDoc.getKind(), is(BindingDoc.Kind.CONSTANT));
+        assertThat(constDoc.getBody(), is("This is the const doc."));
+    }
+
+
+    @Test
+    public void docForUnboundIdentifier()
+        throws FusionException
+    {
+        assertNull(bindingDoc("unbound_var"));
+    }
+
+    @Test
+    public void docForConstant()
+        throws FusionException
+    {
+        BindingDoc doc = bindingDoc("const");
+
+        assertThat(doc.getKind(), is(BindingDoc.Kind.CONSTANT));
+        assertThat(doc.getBody(), is("This is the const doc."));
+    }
+
+    @Test
+    public void docForProcedure()
+        throws FusionException
+    {
+        BindingDoc doc = bindingDoc("proc");
+
+        assertThat(doc.getKind(), is(BindingDoc.Kind.PROCEDURE));
+        assertThat(doc.getBody(), containsString("(proc)"));
+        assertThat(doc.getBody(), containsString("This is the proc doc."));
+    }
+
+    @Test
+    public void docForMacro()
+        throws FusionException
+    {
+        BindingDoc doc = bindingDoc("macro");
+
+        assertThat(doc.getKind(), is(BindingDoc.Kind.SYNTAX));
+        assertThat(doc.getBody(), is("This is the macro doc."));
+    }
+}