style_commaleading.sv

/* Comma-Leading Style
<https://gist.github.com/isaacs/357981>
<https://github.com/tibbe/haskell-style-guide/blob/master/haskell-style.md#list-declarations>
*/

/* Module declaration without parameter ports.
*/
module Mod_A
  ( input  var logic i_abc // comment
  , inout  tri logic b_def /* comment */
  , output var logic o_ghi
  );
endmodule

/* Module declaration with parameter ports.
*/
module Mod_B
  #(int FOO = 1 // comment
  , bit BAR = 2 /* comment */
  , bit [31:0] BAZ = 2
  , parameter int BUZZ = 4
  )
  ( input  var logic i_abc // comment
  , inout  tri logic b_def /* comment */
  , output var logic o_ghi
  );


  /* Each item on its own line.
  - Short lines.
  - Every list indented to same level.
  - Single-line LHS can be any length without indent issue.
  */
  assign {foo, bar} =
    { i_abc
    , 12'h345
    , b_def     // comment
    , 16'h3456  /* comment */
    };

  /* First item on same line (less nice style).
  */
  assign lessnice_A = { i_abc // No indent alignment issue.
                      , 12'h345
                      , b_def
                      , 16'h3456
                      };
  assign lessnice_B_ =  { i_abc // Extra space after `=` to align with indent.
                        , 12'h345
                        , b_def
                        , 16'h3456
                        };


  /* Everything fits on one line.
  - No space after opening parenthesis/bracket/brace.
  */
  assign singleline1D = {i_abc, 12'h345, b_def, 16'h3456};
  assign singleline2D = {{foo, bar}, {foo, bar}, {foo, bar}};

  /* Multi-dimensional concatenation with innermost array on one line.
  */
  assign matrix2D_A =
    { {elem21, elem20}
    , {elem11, elem10} // comment
    , {elem01, elem00} /* comment */
    };
  assign matrix3D_A =
    { { {elem211, elem210}
      , {elem201, elem200}
      }
    , { {elem111, elem110} // comment
      , {elem101, elem100} /* comment */
      }
    , { {elem011, elem010}
      , {elem001, elem000}
      }
    };

  /* Multi-dimensional concatenation with innermost array on multiple lines.
  */
  assign matrix2D_B =
    { { elem21
      , elem20
      }
    , { elem11 // comment
      , elem10 /* comment */
      }
    , { elem01
      , elem00
      }
    };
  assign matrix3D_B =
    { { { elem211
        , elem210
        }
      , { elem201 // comment
        , elem200 /* comment */
        }
      }
    , { { elem110
        , elem110
        }
      , { elem100
        , elem100
        }
      }
    , { { elem010
        , elem010
        }
      , { elem000
        , elem000
        }
      }
    };


  /* Module instance without parameter ports.
  */
  Mod_A u_instanceA
    ( .i_abc(foo) // comment
    , .b_def({bar, bar}) /* comment */
    , .o_ghi
    );

  /* Module instance with parameter ports.
  */
  Mod_B
    #(.FOO(1) // comment
    , .BAR(2) /* comment */
    , .BUZZ(2)
    ) u_instanceB
    ( .i_abc(foo) // comment
    , .b_def({bar, bar}) /* comment */
    , .o_ghi
    );

endmodule