REM > printer library for mal in BBC BASIC

DEF FNpr_str(val%, print_readably%)
  LOCAL ret$, term$, val$
  IF FNis_nil(val%) THEN ="nil"
  IF FNis_boolean(val%) THEN
    IF FNunbox_boolean(val%) THEN ="true" ELSE ="false"
  ENDIF
  IF FNis_int(val%) THEN =STR$(FNunbox_int(val%))
  IF FNis_string(val%) THEN
    val$ = FNunbox_string(val%)
    IF LEFT$(val$, 1) = CHR$(127) THEN =":" + MID$(val$, 2)
    IF print_readably% THEN =FNformat_string(val$) ELSE =val$
  ENDIF
  IF FNis_symbol(val%) THEN =FNunbox_symbol(val%)
  IF FNis_corefn(val%) OR FNis_fn(val%) THEN ="#<function>"
  IF FNis_seq(val%) THEN
    ret$ = "(" : term$ = ")"
    IF FNis_vector(val%) THEN ret$ = "[" : term$ = "]"
    WHILE NOT FNis_empty(val%)
      IF LEN(ret$) > 1 THEN ret$ += " "
      ret$ += FNpr_str(FNfirst(val%), print_readably%)
      val% = FNrest(val%)
    ENDWHILE
    =ret$ + term$
  ENDIF
  IF FNis_hashmap(val%) THEN
    ret$ = "{"
    WHILE NOT FNis_empty_hashmap(val%)
      IF LEN(ret$) > 1 THEN ret$ += " "
      ret$ += FNpr_str(FNalloc_string(FNhashmap_first_key(val%)), print_readably%)
      ret$ += " " + FNpr_str(FNhashmap_first_val(val%), print_readably%)
      val% = FNhashmap_rest(val%)
    ENDWHILE
    =ret$ + "}"
  ENDIF
  IF FNis_atom(val%) THEN
    ="(atom "+FNpr_str(FNatom_deref(val%), print_readably%)+")"
  ENDIF
  ERROR &40E809F0, "Unprintable value"

DEF FNformat_string(strval$)
  LOCAL ptr%, c$, out$
  IF strval$ = "" THEN =""""""
  FOR ptr% = 1 TO LEN(strval$)
    c$ = MID$(strval$, ptr%, 1)
    CASE c$ OF
      WHEN "\", """": out$ += "\" + c$
      WHEN CHR$(10): out$ += "\n"
      OTHERWISE: out$ += c$
    ENDCASE
  NEXT ptr%
="""" + out$ + """"

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