; Convert characters to screen codes

; Macro that converts one character.
; scrbyte() can be used as an instruction operand
.define scrbyte(code)   (<(.strat ("h@dbdlhh", code >> 5) << 4) ^ code)

; Helper macro that stores one character
.macro _scrcode char
        .if (char < 256)
                .byte   scrbyte {char}
        .else
                .error  "scrcode: Character constant out of range"
        .endif
.endmacro

.macro  scrcode arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9

        ; Bail out if next argument is empty
        .if     .blank ({arg1})
                .exitmacro
        .endif

        ; Check for a string
        .if     .match ({arg1}, "")

                ; Walk over all string chars
                .repeat .strlen (arg1), i
                        _scrcode        {.strat (arg1, i)}
                .endrepeat

        ; Check for a number
        .elseif .match (.left (1, {arg1}), 0)

                ; Just output the number
                _scrcode        arg1

        ; Check for a character
        .elseif .match (.left (1, {arg1}), 'a')

                ; Just output the character
                _scrcode        arg1

        ; Anything else is an error
        .else
                .error  "scrcode: invalid argument type"
        .endif

        ; Call the macro recursively with the remaining args
        scrcode arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9
.endmacro