errors.py

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##  THATCHORD BY TOM CONTI-LESLIE                                 errors.py  ##
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##  This file should be loaded by most other files and contains all error    ##
##  messages that can be returned by various files.                          ##
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##  License: CC BY-SA 4.0                                                    ##
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##  Contact: tom (dot) contileslie (at) gmail (dot) com                      ##
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class ChordError(Exception):
    pass

def err(reason):
    
    # REASON 1: INVALID INPUT
    if reason in ("input", 1):
        out = """Invalid chord structure: try a chord of the form """         \
            + """WXYZ", where:\n- W is a letter A-G possibly followed """     \
            + """by "b"or "#";\n- (optional) X is a chord quality, e.g. """   \
            + """"m", "add9", "dim7", ...\n- (optional) Y is a set of """     \
            + """altered notes in parentheses, e.g. "(b7)" or "(#7b13)";\n""" \
            + """- (optional) Z is a bass note, e.g. "/D#"."""
        raise ChordError(out)
    
    # REASON 2: INVALID ALTERATION NUMBER
    if reason in ("alteration", 2):
        out = """Invalid alteration: you can alter the numbers 1, 2, 3, 4, """\
            + """5, 6, 7, 9, 11, 13 only."""
        raise ChordError(out)
    
    # REASON 3: UNRECOGNISED CHORD QUALITY
    if reason in ("quality", 3):
        import dicts
        out = """Unrecognised chord quality. Currently supported chord """    \
            + """qualities are: """ + str(list(dicts.qualities.keys()))       \
            + """. These  are case-sensitive. You can also put alterations """\
            + """in parentheses."""
        raise ChordError(out)
        
    # REASON 4 (FERMAT'S ERROR): MARGIN TOO SMALL TO PRINT LINE NUMBER
    if reason in ("fermat", 4):
        out = """In attempting to print a chord, one line number to be """    \
            + """displayed was too long compared to the default margin size"""\
            + """. Ensure ThatChord is not printing chords absurdly high """  \
            + """on the fretboard, and that the margin is defined to be """   \
            + """suitably large (ideally 3 or more; at least 1)."""
        raise ChordError(out)
    
    # REASON 5: TOO FEW FRETS FOR ANY POSSIBILITIES
    if reason in ("frets", 5):
        out = """The number of frets is too low for one of your """           \
            + """instrument strings to have any valid positions. Try """      \
            + """changing the number of frets, changing the chord, or """     \
            + """allowing more muted strings."""
        raise ChordError(out)
        
    # REASON 6: NO CHORDS FOUND
    if reason in ("nosols", 6):
        out = """There are no ways of playing the requested chord on this """ \
            + """instrument, though your chord was correctly understood. """  \
            + """Try increasing the number of frets or reducing the number """\
            + """of important notes."""
        raise ChordError(out)
    
    # REASON 7: INVALID INPUT TYPE
    if reason in ("input type", 7):
        out = """Invalid input type: in the settings file, please set the """ \
            + """variable input_type to be DIRECT, TERMINAL or CONSOLE."""
        raise ChordError(out)
    
    # REASON 8: INVALID OUTPUT FORMAT
    if reason in ("output format", 8):
        out = """Invalid output format: in the settings file, please set """  \
            + """the variable output_format to be TEXT or PNG."""
        raise ChordError(out)
    
    # REASON 9: INVALID OUTPUT METHOD
    if reason in ("output method", 9):
        out = """Invalid output method: in the settings file, please set """  \
            + """the variable output_method to be PRINT, SPLASH or NONE."""
        raise ChordError(out)
    
    # REASON 10: INVALID SAVE METHOD
    if reason in ("save method", 10):
        out = """Invalid save method: in the settings file, please set the """\
            + """variable save_method to be SINGLE, LIBRARY or NONE."""
        raise ChordError(out)
    
    # REASON 11: INCOMPATIBLE OUTPUT SETTINGS
    if reason in ("incompatible output", 11):
        out = """You have chosen incompatible values of output_format and """ \
            + """output_method. See settings.py to correct this."""
        raise ChordError(out)
    
    # REASON 12: SAVE DIRECTORY DOESN'T EXIST
    if reason in ("file not found", 12):
        out = """The output location could not be found. If you have not """  \
            + """tweaked the settings too much, this can probably be fixed """\
            + """by creating a new folder inside the ThatChord folder """     \
            + """called 'diagrams' (all lowercase). If you have done some """ \
            + """tweaking, then please check that the output directory """    \
            + """specified in settings.py exists."""
        raise ChordError(out)
    
    # REASON 13: CUSTOM INPUT NOT RECOGNISED
    if reason in ("custom", 13):
        out = """Custom input not recongised. To enter a chord note by note"""\
            + """, type "CUSTOM" followed by a list of notes separated by """ \
            + """spaces or commas. Notes can be entered as e.g. 'C#', 'G', """\
            + """'Bb', or as numbers 0-11 (0=C, 1=C#, ...).\nIt may also be"""\
            + """ that your custom tuning contains no notes."""
        raise ChordError(out)
    
    # REASON 14: TOO MANY COLONS IN INPUT
    if reason in ("colons", 14):
        out = """There are too many colons in your input. Adding a ":" at """ \
            + """the end of your chord request requests a specific index of"""\
            + """ chord in the list of possibilities. There must be at most"""\
            + """ one colon in the input."""
        raise ChordError(out)
    
    # REASON 15: CANNOT UNDERSTAND LIST INDEX REQUESTED
    if reason in ("aftercolon", 15):
        out = """You have requested a specific index of chord in the list """ \
            + """of possibilities by using a colon but I don't understand """ \
            + """what index this is. Please follow a colon simply by a """    \
            + """number, e.g. 'Cmaj7:2' if you want to see the second best """\
            + """match for Cmaj7."""
        raise ChordError(out)
    
    # REASON 16: LIST INDEX REQUESTED TOO HIGH
    # N.B. deprecated since faster restructure which, for a too high index,
    # simply returns the worst we've got.
    if reason in ("fewoptions", 16):
        out = """You have requested a solution number which is greater than"""\
            + """ the number of solutions found. Please request a lower """   \
            + """index after the colon."""
        raise ChordError(out)
    
    # REASON 17: LISTS IN SETTINGS NOT OF SAME LENGTH
    if reason in ("lenlists", 17):
        out = """In the settings file, please ensure that the variables """   \
            + """"tuning" and "order" have the same length."""
        raise ChordError(out)
    
    # REASON 18: STRINGSTARTS IS TOO SHORT
    if reason in ("stringstarts", 18):
        out = """In the settings file, please ensure that the variable """    \
            + """"stringstarts" is at least as long as the number of frets."""
        raise ChordError(out)
    
    # REASON 19: SETTINGS YML FILE NOT FOUND
    if reason in ("settingsnotfound", 19):
        out = """Could not find the settings.yml file. Please ensure that a"""\
            + """ file with that name is in your ThatChord folder."""
        raise ChordError(out)
    
    # REASON 20: SETTINGS MISSING
    if reason in ("settingsmissing", 20):
        out = """Some bullet points are missing from the settings.yml file."""\
            + """ Please ensure it contains points: presets; input; output;"""\
            + """ saving; custom_instrument; custom_ranking; graphical_p"""   \
            + """arameters."""
        raise ChordError(out)
        
    # REASON 21: TOO MANY @ SIGNS IN INPUT
    if reason in ("ats", 21):
        out = """There are too many @ signs in your input. Adding an "@" """  \
            + """sign after your chord sets a minimum fret height that the""" \
            + """ chord must be played at. There must be at most one "a\""""  \
            + """ sign in the input."""
        raise ChordError(out)
    
    # REASON 22: CANNOT UNDERSTAND FRET SPECIFICATION
    if reason in ("afterat", 22):
        out = """You have requested a minimum fret height by using an @ """   \
            + """sign, but I don't understand what fret you have requested."""\
            + """ Please ensure that the @ sign is followed by an integer, """\
            + """e.g. 'Cmaj7@5'. The number after the @ sign can optionally"""\
            + """be followed by a colon, e.g. 'Cmaj7@5:2'."""
        raise ChordError(out)
    
    if reason in ("highfretspec", 23):
        out = """You have requested a minimal fret height which is greater """\
            + """than the number of frets on your instrument. Please enter """\
            + """a lower number after the @ symbol, or increase your number"""\
            + """ of frets."""
        raise ChordError(out)
    
    raise ChordError(str(reason))