Fix/scl language support

internal/config/allowlist/scl_ext_test.go

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright 2026 alibaba/open-code-review Contributors
+
+package allowedext
+
+import "testing"
+
+func TestSCLIsAllowedCaseInsensitive(t *testing.T) {
+	for _, ext := range []string{".scl", ".SCL"} {
+		t.Run(ext, func(t *testing.T) {
+			if !IsAllowedExt(ext) {
+				t.Fatalf("IsAllowedExt(%q) = false, want true", ext)
+			}
+		})
+	}
+}

internal/config/allowlist/supported_file_types.json

@@ -109,5 +109,6 @@
   ".vhdl",
   ".sol",
   ".vy",
-  ".rego"
+  ".rego",
+  ".scl"
 ]

internal/config/rules/rule_docs/scl.md

@@ -0,0 +1,34 @@
+#### Siemens SCL Review Principles
+> Focus on defects that can change PLC behavior, safety, determinism, or runtime reliability. SCL (Structured Control Language) is a Pascal-based textual PLC language aligned with IEC 61131-3 Structured Text. Do not flag ordinary Pascal-like syntax or vendor-specific conventions unless the changed code demonstrates a concrete correctness problem.
+
+#### Control Flow and State
+- Conditions that accidentally omit a required branch, especially when the omitted state leaves an output, command, or state variable holding a stale value
+- `CASE` statements that do not cover an expected value when the uncovered state can produce unsafe or incorrect machine behavior
+- State-machine transitions that make a state unreachable, create an unintended transition loop, or leave the machine with no valid successor
+- Repeated writes to the same control variable in one scan where later assignments can silently override an earlier decision
+
+#### Loops and Scan-Time Safety
+- Loops whose termination depends on mutable PLC state without a clear progress condition
+- Unbounded or unexpectedly large loops in cyclic program execution when they can exceed the expected scan-time budget or starve time-critical logic
+- Busy-wait loops used where a state transition, timer, or other PLC-supported sequencing mechanism is needed
+
+#### Data Types and Numeric Correctness
+- Implicit conversions or narrowing assignments that can truncate a value, change signedness, or lose precision in a way that affects control logic
+- Arithmetic whose range can exceed the target data type, especially counters, timers, indexes, and accumulated values
+- Array indexing that can reach outside the declared bounds because the index is derived from runtime input or an unchecked calculation
+- Comparisons between values with incompatible or unintended types where the result can differ from the programmer's apparent intent
+
+#### I/O and Persistent Data
+- Writing outputs or persistent state before required validity, mode, or interlock checks have completed
+- Reading an input once and then using a stale snapshot across logic that can change the relevant machine state within the same scan
+- Resetting, overwriting, or reinitializing retained/process data unexpectedly, causing loss of state across cycles or restarts
+
+#### Error Handling and External Blocks
+- Ignoring a status/error result from a called block or communication operation when the caller continues as though the operation succeeded
+- Using data produced by a block, timer, counter, or communication interface before establishing that the result is valid for the current state
+- Error paths that leave an actuator command, mode bit, or state variable in an unsafe or contradictory condition
+
+#### Maintainability with Behavioral Impact
+- Duplicated control conditions that can diverge after a change and cause two parts of the sequence to make conflicting decisions
+- Magic constants used for operational limits where the value is part of a safety, timing, or process invariant and can be changed independently of the corresponding logic
+- Dead branches or unreachable code when their presence can hide a missing transition or an incomplete safety condition

internal/config/rules/scl_rules_test.go

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright 2026 alibaba/open-code-review Contributors
+
+package rules
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestResolve_SCLRule(t *testing.T) {
+	rule, err := LoadDefault()
+	if err != nil {
+		t.Fatalf("LoadDefault: %v", err)
+	}
+
+	for _, path := range []string{"main.scl", "plc/Blocks/Motor.SCL", "src/control.scl"} {
+		t.Run(path, func(t *testing.T) {
+			got := rule.Resolve(path)
+			if !strings.Contains(got, "Siemens SCL Review Principles") {
+				t.Fatalf("Resolve(%q): expected Siemens SCL rule, got %q", path, truncate(got, 120))
+			}
+		})
+	}
+}

internal/config/rules/system_rules.json

@@ -52,6 +52,7 @@
     "**/*.mm": "objc.md",
     "**/*.sol": "solidity.md",
     "**/*.vy": "vyper.md",
-    "**/*.rego": "rego.md"
+    "**/*.rego": "rego.md",
+    "**/*.scl": "scl.md"
   }
 }