message: doc for operators
diff: #pragma once
  enum OperatorType {
  - RANGE,
  - INDEX,
  - DOWNTO,
  - TO,
  - SUB,
  - ADD,
  + RANGE, // range used in VHDL type specifications
  + INDEX, // array index
  + DOWNTO, // downto for the slice specification
  + TO, // to for the slice specification
  + SUB, // can also be unary minus
  + ADD, // can also be unary plus
  DIV,
  MUL,
  MOD,
  REM,
  - CONCAT,
  - POW,
  - ABS,
  + CONCAT,// concatenation of signals
  + POW, // bin operator power of
  + ABS, // absolute val
  NOT,
  - NEG,
  + NEG, // negation
  LOG_AND,
  LOG_OR,
  AND,
  @@ -24,24 +24,24 @@ enum OperatorType {
  NOR,
  XOR,
  XNOR,
  - EQ,
  - NEQ,
  - LOWERTHAN,
  - LE,
  - GREATERTHAN,
  - GE,
  - SLL,
  - SRL,
  - SLA,
  - SRA,
  - ROL,
  - ROR,
  + EQ, // ==
  + NEQ, // ~
  + LOWERTHAN, // <
  + LE, // <=
  + GREATERTHAN, // >
  + GE, // >=
  + SLL, // shift left logical
  + SRL, // shift right logical
  + SLA, // shift left arithmetical
  + SRA, // shift right arithmetical
  + ROL, // rotate left
  + ROR, // rotate right
  TERNARY,
  DOT,
  CALL,
  - ARROW,
  - RISING,
  - FALLING,
  + ARROW, // arrow operator used in vhdl type descriptions
  + RISING, // rising edge/posedge event operator
  + FALLING,// falling edge/negedge event operator
  };
  const char* OperatorType_toString(OperatorType opt);
  