X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=bundles%2Forg.simantics.scl.compiler%2Fsrc%2Forg%2Fsimantics%2Fscl%2Fcompiler%2Finternal%2Fderiving%2FJsonDeriver.java;fp=bundles%2Forg.simantics.scl.compiler%2Fsrc%2Forg%2Fsimantics%2Fscl%2Fcompiler%2Finternal%2Fderiving%2FJsonDeriver.java;h=24f8b316230547bab65c614a6359587e28d1a14f;hb=22b86b38b00d6e168a5872e70113efd5fc1d81b6;hp=0000000000000000000000000000000000000000;hpb=66b0fd2ee69d84d3107f109679b6fd1866f8f3fc;p=simantics%2Fplatform.git

diff --git a/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/internal/deriving/JsonDeriver.java b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/internal/deriving/JsonDeriver.java
new file mode 100644
index 000000000..24f8b3162
--- /dev/null
+++ b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/internal/deriving/JsonDeriver.java
@@ -0,0 +1,218 @@
+package org.simantics.scl.compiler.internal.deriving;
+
+import java.util.ArrayList;
+
+import org.simantics.scl.compiler.common.datatypes.Constructor;
+import org.simantics.scl.compiler.common.names.Names;
+import org.simantics.scl.compiler.constants.StringConstant;
+import org.simantics.scl.compiler.elaboration.errors.NotPatternException;
+import org.simantics.scl.compiler.elaboration.expressions.EApply;
+import org.simantics.scl.compiler.elaboration.expressions.EConstant;
+import org.simantics.scl.compiler.elaboration.expressions.EListLiteral;
+import org.simantics.scl.compiler.elaboration.expressions.ELiteral;
+import org.simantics.scl.compiler.elaboration.expressions.ERecord;
+import org.simantics.scl.compiler.elaboration.expressions.EVar;
+import org.simantics.scl.compiler.elaboration.expressions.Expression;
+import org.simantics.scl.compiler.elaboration.expressions.records.FieldAssignment;
+import org.simantics.scl.compiler.elaboration.modules.SCLValue;
+import org.simantics.scl.compiler.elaboration.modules.TypeAlias;
+import org.simantics.scl.compiler.elaboration.modules.TypeConstructor;
+import org.simantics.scl.compiler.elaboration.modules.TypeDescriptor;
+import org.simantics.scl.compiler.environment.AmbiguousNameException;
+import org.simantics.scl.compiler.environment.Environment;
+import org.simantics.scl.compiler.environment.Environments;
+import org.simantics.scl.compiler.errors.ErrorLog;
+import org.simantics.scl.compiler.internal.parsing.declarations.DDerivingInstanceAst;
+import org.simantics.scl.compiler.internal.parsing.declarations.DInstanceAst;
+import org.simantics.scl.compiler.internal.parsing.declarations.DValueAst;
+import org.simantics.scl.compiler.internal.parsing.translation.ProcessedDInstanceAst;
+import org.simantics.scl.compiler.internal.parsing.translation.ValueRepository;
+import org.simantics.scl.compiler.internal.parsing.types.TVarAst;
+import org.simantics.scl.compiler.types.TApply;
+import org.simantics.scl.compiler.types.TCon;
+import org.simantics.scl.compiler.types.Type;
+import org.simantics.scl.compiler.types.Types;
+
+class JsonDeriver implements InstanceDeriver {
+
+    @Override
+    public void derive(
+            ErrorLog errorLog,
+            Environment environment,
+            ArrayList<ProcessedDInstanceAst> instancesAst,
+            DDerivingInstanceAst der) {
+        // Analyze
+        if(der.types.length != 1) {
+            errorLog.log(der.location, "Invalid number of parameters to " + der.name);
+            return;
+        }
+        TVarAst headType = DerivingUtils.getHeadType(der.types[0]);
+        if(headType == null) {
+            errorLog.log(der.types[0].location, "Cannot derive Json instance for the type " + headType + ".");
+            return;
+        }
+        TCon con;
+        try {
+            con = Environments.getTypeDescriptorName(environment, headType.name);
+        } catch (AmbiguousNameException e1) {
+            errorLog.log(headType.location, e1.getMessage());
+            return;
+        }
+        if(con == null) {
+            errorLog.log(headType.location, "Couldn't resolve " + headType.name);
+            return;
+        }
+        TypeDescriptor tdesc = environment.getTypeDescriptor(con);
+        if(tdesc == null) {
+            errorLog.log(headType.location, "Didn't find type constructor for " + headType.name);
+            return;
+        }
+        if(tdesc instanceof TypeAlias) {
+            errorLog.log(headType.location, "Cannot derive instance for a type alias.");
+            return;
+        }
+        TypeConstructor tcon = (TypeConstructor)tdesc;
+        if(tcon.isOpen) {
+            errorLog.log(headType.location, "Cannot derive instance for open data types.");
+            return;
+        }
+
+        if(tcon.constructors.length != 1) {
+            errorLog.log(headType.location, "Data must have exactly one constructor for deriving to work.");
+            return;
+        }
+        Constructor constructor = tcon.constructors[0];
+        if(constructor.recordFieldNames == null) {
+            errorLog.log(headType.location, "Data must have a record constructor for deriving to work.");
+            return;
+        }
+
+        DInstanceAst instanceAst = new DInstanceAst(der.location, der.context, der.name, der.types);
+        ValueRepository valueDefs = new ValueRepository();
+
+        SCLValue fromJson = environment.getValue(Names.Json_fromJson);
+        SCLValue toJson = environment.getValue(Names.Json_toJson);
+        SCLValue lookupJsonField = environment.getValue(Names.Json_lookupJsonField);
+        SCLValue JsonObject = environment.getValue(Names.Json_JsonObject);
+        SCLValue JsonField = environment.getValue(Names.Json_JsonField);
+        
+        SCLValue Just = environment.getValue(Names.Builtin_Just);
+        SCLValue fromJust = environment.getValue(Names.Prelude_fromJust);
+        SCLValue map = environment.getValue(Names.Prelude_map);
+        SCLValue filterJust = environment.getValue(Names.Prelude_filterJust);
+        SCLValue dot = environment.getValue(Names.Prelude_dot);
+
+        // Collect all relevant information about the constructor
+        String constructorName = constructor.name.name;
+        int fieldCount = constructor.parameterTypes.length;
+        String[] fieldNames = constructor.recordFieldNames;
+        boolean[] isOptional = new boolean[fieldCount];
+        boolean hasAtLeastOneOptional = false;
+        for(int i=0;i<fieldCount;++i) {
+            Type type = constructor.parameterTypes[i];
+            hasAtLeastOneOptional |= isOptional[i] = type instanceof TApply
+                    && ((TApply)type).function == Types.MAYBE;
+        }
+
+        // Generate toJson
+        {
+            /* toJson GeographicalLocation { latitude, longitude } = JsonObject [
+             *     JsonField "latitude" (toJson latitude),
+             *     JsonField "longitude" (toJson longitude)
+             * ]
+             * toJson GeographicalLocation { latitude, longitude } = JsonObject $ filterJust [
+             *     Just (JsonField "latitude" (toJson latitude)),
+             *     map (JsonField "longitude" . toJson) longitude
+             * ]
+             */
+            FieldAssignment[] fieldAssignments = new FieldAssignment[fieldCount];
+            for(int i=0;i<fieldCount;++i)
+                fieldAssignments[i] = new FieldAssignment(fieldNames[i], null);
+            Expression lhs = new EApply(
+                    new EVar("toJson"),
+                    new ERecord(new EVar(constructorName), fieldAssignments)
+                    );
+            Expression componentsExpression;
+            if(hasAtLeastOneOptional) {
+                Expression[] components = new Expression[fieldCount];
+                for(int i=0;i<fieldCount;++i) {
+                    if(isOptional[i])
+                        components[i] = new EApply(new EConstant(map),
+                                new EApply(new EConstant(dot),
+                                        new EApply(new EConstant(JsonField), new ELiteral(new StringConstant(fieldNames[i]))),
+                                        new EConstant(toJson)
+                                        ),
+                                new EVar(fieldNames[i])
+                                );
+                    else
+                        components[i] = new EApply(new EConstant(Just),
+                                new EApply(new EConstant(JsonField),
+                                        new ELiteral(new StringConstant(fieldNames[i])),
+                                        new EApply(new EConstant(toJson), new EVar(fieldNames[i]))
+                                        ));
+                }
+                componentsExpression = new EApply(new EConstant(filterJust),
+                        new EListLiteral(components));
+            }
+            else {
+                Expression[] components = new Expression[fieldCount];
+                for(int i=0;i<fieldCount;++i) {
+                    components[i] = new EApply(new EConstant(JsonField),
+                            new ELiteral(new StringConstant(fieldNames[i])),
+                            new EApply(new EConstant(toJson), new EVar(fieldNames[i]))
+                            );
+                }
+                componentsExpression = new EListLiteral(components);
+            }
+            Expression rhs = new EApply(new EConstant(JsonObject), componentsExpression);
+            try {
+                DValueAst valueAst = new DValueAst(lhs, rhs);
+                valueAst.setLocationDeep(der.location);
+                valueDefs.add(valueAst);
+            } catch (NotPatternException e) {
+                errorLog.log(e.getExpression().location, "Not a pattern (a).");
+            }
+        }
+
+        // Generate fromJson
+        {
+            /* fromJson object = GeographicalLocation {
+             *     latitude = fromJson $ fromJust $ lookupJsonField "latitude" object,
+             *     longitude = map fromJson $ lookupJsonField "longitude" object
+             * }
+             */
+            Expression lhs = new EApply(
+                    new EVar("fromJson"),
+                    new EVar("jsonObject")
+                    );
+            FieldAssignment[] fieldAssignments = new FieldAssignment[fieldCount];
+            for(int i=0;i<fieldCount;++i) {
+                Expression fieldValue = new EApply(new EConstant(lookupJsonField),
+                        new ELiteral(new StringConstant(fieldNames[i])),
+                        new EVar("jsonObject")
+                        );
+                if(isOptional[i]) {
+                    fieldValue = new EApply(new EConstant(map), new EConstant(fromJson), fieldValue);
+                }
+                else {
+                    fieldValue = new EApply(new EConstant(fromJust), fieldValue);
+                    fieldValue = new EApply(new EConstant(fromJson), fieldValue);
+                }
+                fieldAssignments[i] = new FieldAssignment(fieldNames[i], fieldValue);
+            }
+            Expression rhs = new ERecord(new EVar(constructorName),
+                    fieldAssignments
+                    );
+            try {
+                DValueAst valueAst = new DValueAst(lhs, rhs);
+                valueAst.setLocationDeep(der.location);
+                valueDefs.add(valueAst);
+            } catch (NotPatternException e) {
+                errorLog.log(e.getExpression().location, "Not a pattern (b).");
+            }
+        }
+
+        instancesAst.add(new ProcessedDInstanceAst(instanceAst, valueDefs));
+    }
+
+}