true and
false are built in constants. See Appendix A.5.2.
Input Pins.
true and false also automatically expand to match input bus width, which is really useful. See Appendix A.5.3
Buses.
Here's a handy chip that converts a single-bit wire to a 16-bit bus (all 16 output bits will have the same value as in) that uses true and false with buses.
/**
* Bus16: expand 1-bit 'in' to 16-bit 'out'.
*/
CHIP Bus16 {
IN in;
OUT out[16];
PARTS:
Mux16(a=false, b=true, sel=in, out=out);
}
--Mark