LAPLACE Phase5

Author: marcin-golebiowski

roadmap/laplace-pspice-feasibility.md

@@ -68,7 +68,7 @@ This approach keeps the implementation small, aligns with existing source-genera
 
 ## Current Status
 
-Canonical `E`-source and `G`-source `LAPLACE` support is implemented by SpiceSharpParser. `F`, `H`, `B`, alternate syntaxes, delay, and `M=` support remain deferred.
+`E`-source and `G`-source `LAPLACE` support is implemented by SpiceSharpParser for canonical assignment, no-equals expression-pair, and equals-after-keyword expression-pair syntax. `F`, `H`, `B`, function-like `VALUE={LAPLACE(...)}`, delay, and `M=` support remain deferred.
 
 Phase 1 grammar groundwork is implemented: expression-to-expression assignments such as `{V(in)} = {1/(1+s*tau)}` and `{V(in1,in2)} = {1/(1+s*tau)}` are preserved as `ExpressionAssignmentParameter`.
 
@@ -78,6 +78,8 @@ Phase 3 `E`-source mapping is implemented: canonical `Ename out+ out- LAPLACE {V
 
 Phase 4 `G`-source mapping is implemented: canonical `Gname out+ out- LAPLACE {V(ctrl)}` `= {H(s)}` and `V(ctrl+,ctrl-)` forms map to `LaplaceVoltageControlledCurrentSource`, preserve the existing `G` current-source sign convention, reject unsupported `M=` / delay options, and have OP / AC integration coverage.
 
+Phase 5 syntax compatibility is implemented: `E` / `G` sources accept `LAPLACE {V(...)} = {H(s)}`, `LAPLACE {V(...)} {H(s)}`, and `LAPLACE = {V(...)} {H(s)}` as equivalent voltage-controlled forms, while known deferred `VALUE={LAPLACE(...)}` and `B`-source forms produce targeted reader diagnostics.
+
 Adjacent features already exist:
 
 - `VALUE={expr}` behavioral sources.
@@ -598,9 +600,9 @@ The last recognizer is deliberate. If a user writes a known PSpice Laplace varia
 
 | Family | Example | Near-term behavior | Notes |
 |--------|---------|--------------------|-------|
-| Canonical assignment | `E1 out 0 LAPLACE {V(in)} = {1/(1+s*tau)}` | Support first | Exercises grammar gap and runtime mapping. |
-| No-equals expression pair | `E1 out 0 LAPLACE {V(in)} {1/(1+s*tau)}` | Add after canonical | Should normalize to the same definition and coefficients. |
-| Equals-after-keyword pair | `E1 out 0 LAPLACE = {V(in)} {1/(1+s*tau)}` | Add after canonical | Likely parses differently; keep syntax handling isolated in a recognizer. |
+| Canonical assignment | `E1 out 0 LAPLACE {V(in)} = {1/(1+s*tau)}` | Supported | Exercises grammar gap and runtime mapping. |
+| No-equals expression pair | `E1 out 0 LAPLACE {V(in)} {1/(1+s*tau)}` | Supported | Normalizes to the same definition and coefficients. |
+| Equals-after-keyword pair | `E1 out 0 LAPLACE = {V(in)} {1/(1+s*tau)}` | Supported | Parses differently; syntax handling stays isolated in a recognizer. |
 | Current-controlled | `F1 out 0 LAPLACE {I(Vsense)} = {H(s)}` | Later milestone | Runtime entities exist, but controlling-source parsing and PSpice compatibility need tests. |
 | Function-like `VALUE` | `E1 out 0 VALUE = {LAPLACE(V(in), H(s))}` | Investigate later | Must be handled as source-level Laplace, not a scalar expression function. |
 | `B` source ABM | `B1 out 0 V = {LAPLACE(V(in), H(s))}` | Investigate later | May require arbitrary input-expression lowering or custom behavior. |
@@ -676,6 +678,8 @@ Status: implemented for canonical `G` source syntax. `M=`, delay options, `F`, a
 
 ### Phase 5: Syntax Compatibility Layer
 
+Status: implemented for `E` / `G` no-equals and equals-after-keyword voltage-controlled syntax. `VALUE={LAPLACE(...)}`, `B`, `F`, `H`, `M=`, and delay options remain diagnostic-only / deferred.
+
 1. Add `UnsupportedKnownVariantRecognizer` so common deferred forms receive targeted diagnostics.
 2. Add `NoEqualsExpressionPairRecognizer` for `LAPLACE {input} {transfer}` only after canonical tests pass.
 3. Add `EqualsExpressionPairRecognizer` for `LAPLACE = {input} {transfer}` only after no-equals tests pass.

src/SpiceSharpParser.IntegrationTests/AnalogBehavioralModeling/LaplaceTests.cs

@@ -84,6 +84,26 @@ public void When_ELaplaceLowPassUsesDifferentialInput_Expect_ControlNodeDifferen
             Assert.True(EqualsWithTol(1.5, export), $"Expected OP gain from differential input near 1.5, got {export}.");
         }
 
+        [Fact]
+        public void When_ELaplaceNoEqualsSyntaxRunsOp_Expect_DcGainNearOne()
+        {
+            var model = GetSpiceSharpModel(
+                "E LAPLACE no-equals OP",
+                ".PARAM tau=1u",
+                "VIN in 0 1",
+                "ELOW out 0 LAPLACE {V(in)} {1/(1+s*tau)}",
+                "RLOAD out 0 1k",
+                ".OP",
+                ".SAVE V(out)",
+                ".END");
+
+            AssertNoValidationErrors(model);
+            Assert.IsType<LaplaceVoltageControlledVoltageSource>(model.Circuit["ELOW"]);
+
+            double export = RunOpSimulation(model, "V(out)");
+            Assert.True(EqualsWithTol(1.0, export), $"Expected OP gain near 1, got {export}.");
+        }
+
         [Fact]
         public void When_ELaplaceLowPassRunsAcAtCutoff_Expect_ExpectedMagnitudeAndPhase()
         {
@@ -184,6 +204,27 @@ public void When_GLaplaceLowPassUsesDifferentialInput_Expect_ControlNodeDifferen
             Assert.True(EqualsWithTol(-1.5, export), $"Expected OP load voltage from differential input near -1.5, got {export}.");
         }
 
+        [Fact]
+        public void When_GLaplaceEqualsAfterKeywordSyntaxRunsOp_Expect_LoadVoltageWithCurrentSourceSign()
+        {
+            var model = GetSpiceSharpModel(
+                "G LAPLACE equals-after-keyword OP",
+                ".PARAM gm=1m",
+                ".PARAM tau=1u",
+                "VIN in 0 1",
+                "GLOW out 0 LAPLACE = {V(in)} {gm/(1+s*tau)}",
+                "RLOAD out 0 1k",
+                ".OP",
+                ".SAVE V(out)",
+                ".END");
+
+            AssertNoValidationErrors(model);
+            Assert.IsType<LaplaceVoltageControlledCurrentSource>(model.Circuit["GLOW"]);
+
+            double export = RunOpSimulation(model, "V(out)");
+            Assert.True(EqualsWithTol(-1.0, export), $"Expected OP load voltage near -1, got {export}.");
+        }
+
         [Fact]
         public void When_GLaplaceLowPassRunsAcAtCutoff_Expect_ExpectedMagnitudeAndPhase()
         {
@@ -319,6 +360,36 @@ public void When_GLaplaceUnsupportedMultiplierIsUsed_Expect_ReaderValidationErro
             AssertReaderErrorContains(model, "multiplier");
         }
 
+        [Fact]
+        public void When_ValueLaplaceFunctionIsUsed_Expect_ReaderValidationError()
+        {
+            var model = GetSpiceSharpModel(
+                "E VALUE LAPLACE unsupported",
+                "VIN in 0 1",
+                "EBAD out 0 VALUE = {LAPLACE(V(in), 1/(1+s))}",
+                "RLOAD out 0 1k",
+                ".OP",
+                ".SAVE V(out)",
+                ".END");
+
+            AssertReaderErrorContains(model, "function syntax");
+        }
+
+        [Fact]
+        public void When_BVoltageLaplaceFunctionIsUsed_Expect_ReaderValidationError()
+        {
+            var model = GetSpiceSharpModel(
+                "B LAPLACE unsupported",
+                "VIN in 0 1",
+                "BBAD out 0 V={LAPLACE(V(in), 1/(1+s))}",
+                "RLOAD out 0 1k",
+                ".OP",
+                ".SAVE V(out)",
+                ".END");
+
+            AssertReaderErrorContains(model, "function syntax");
+        }
+
         [Fact]
         public void When_HLaplaceIsUsed_Expect_ReaderValidationError()
         {