drop timeunit and timescale (closes #31)

src/Language/SystemVerilog/Parser/Lex.x

@@ -85,6 +85,13 @@ $decimalDigit = [0-9]
 
 @string = \" (\\\"|[^\"\r\n])* \"
 
+-- Times
+
+@timeUnit = s | ms | us | ns | ps | fs
+@time
+    = @unsignedNumber @timeUnit
+    | @fixedPointNumber @timeUnit
+
 -- Identifiers
 
 @escapedIdentifier = "\" ($printable # $white)+ $white
@@ -364,6 +371,7 @@ tokens :-
 
     @number            { tok Lit_number }
     @string            { tok Lit_string }
+    @time              { tok Lit_time }
 
     "("                { tok Sym_paren_l }
     ")"                { tok Sym_paren_r }

src/Language/SystemVerilog/Parser/Parse.y

@@ -281,6 +281,7 @@ escapedIdentifier  { Token Id_escaped      _ _ }
 systemIdentifier   { Token Id_system       _ _ }
 number             { Token Lit_number      _ _ }
 string             { Token Lit_string      _ _ }
+time               { Token Lit_time        _ _ }
 
 "("                { Token Sym_paren_l _ _ }
 ")"                { Token Sym_paren_r _ _ }
@@ -738,10 +739,15 @@ NonDeclPackageItem :: { [PackageItem] }
   | "export" PackageImportItems ";" { map (Export .  Just) $2 }
   | "export" "*" "::" "*" ";"       { [Export Nothing] } -- "Nothing" being no restrictions
   | ForwardTypedef ";"              { $1 }
+  | TimeunitsDeclaration            { $1 }
 ForwardTypedef :: { [PackageItem] }
   : "typedef" "enum"   Identifier { [] }
   | "typedef" "struct" Identifier { [] }
   | "typedef" "union"  Identifier { [] }
+TimeunitsDeclaration :: { [PackageItem] }
+  : "timeunit" Time          ";" { [] }
+  | "timeunit" Time "/" Time ";" { [] }
+  | "timeprecision" Time     ";" { [] }
 
 PackageImportItems :: { [(Identifier, Maybe Identifier)] }
   : PackageImportItem                        { [$1] }
@@ -970,6 +976,9 @@ Number :: { String }
 String :: { String }
   : string { tail $ init $ tokenString $1 }
 
+Time :: { String }
+  : time { tokenString $1 }
+
 CallArgs :: { Args }
   : {- empty -}                        { Args [            ] [] }
   |                NamedCallArgsFollow { Args [            ] $1 }

src/Language/SystemVerilog/Parser/Tokens.hs

@@ -281,9 +281,9 @@ data TokenName
     | Id_simple
     | Id_escaped
     | Id_system
-    | Lit_number_unsigned
     | Lit_number
     | Lit_string
+    | Lit_time
     | Sym_paren_l
     | Sym_paren_r
     | Sym_brack_l

test/basic/time.sv

+`timescale 1ns / 10ps
+timeunit 100ps;
+timeprecision 1ps;
+module top_1;
+    `timescale 1ns / 10ps
+    timeunit 1ps;
+    timeprecision 1ps;
+endmodule
+module top_2;
+    timeunit 100ps / 10fs;
+endmodule
+module top_3;
+    timeunit 10.0ps / 10fs;
+endmodule
+module top_4;
+    timeunit 100ps;
+    timeprecision 10fs;
+endmodule
+module top;
+    initial $display("Hello!");
+endmodule

test/basic/time.v

+module top;
+    initial $display("Hello!");
+endmodule