conversion for always_latch (resolves #54)

src/Convert/AlwaysKW.hs

 {- sv2v
  - Author: Zachary Snow <zach@zachjs.com>
  -
- - Conversion for `always_comb` and `always_ff`
+ - Conversion for `always_latch`, `always_comb`, and `always_ff`
  -
+ - `always_latch` -> `always @*`
  - `always_comb` -> `always @*`
  - `always_ff` -> `always`
  -}
@@ -16,6 +17,8 @@ convert :: [AST] -> [AST]
 convert = map $ traverseDescriptions $ traverseModuleItems replaceAlwaysKW
 
 replaceAlwaysKW :: ModuleItem -> ModuleItem
+replaceAlwaysKW (AlwaysC AlwaysLatch stmt) =
+    AlwaysC Always $ Timing (Event SenseStar) stmt
 replaceAlwaysKW (AlwaysC AlwaysComb stmt) =
     AlwaysC Always $ Timing (Event SenseStar) stmt
 replaceAlwaysKW (AlwaysC AlwaysFF stmt) =

test/basic/always_latch.sv

+module test(a, b, en);
+    output logic a;
+    input logic b;
+    input logic en;
+    always_latch begin
+        if (en) begin
+            a <= b;
+        end
+    end
+endmodule

test/basic/always_latch.v

+module test(a, b, en);
+    output reg a;
+    input wire b;
+    input wire en;
+    always @(*) begin
+        if (en) begin
+            a <= b;
+        end
+    end
+endmodule

test/basic/always_latch_tb.v

+module top;
+    wire a;
+    reg b;
+    reg en;
+
+    initial begin
+        en = 1;
+        forever #1 en = ~en;
+    end
+
+    test m(.a, .b, .en);
+
+    initial begin
+        $monitor($time, a, b, en);
+        #1; b = 1;
+        #1; b = 0;
+        #1; b = 0;
+        #1; b = 1;
+        #1; b = 0;
+        $finish;
+    end
+endmodule