# Licensed under a 3-clause BSD style license - see LICENSE.rst
# This module includes files automatically generated from ply (these end in
# _lextab.py and _parsetab.py). To generate these files, remove them from this
# folder, then build astropy and run the tests in-place:
#
# python setup.py build_ext --inplace
# pytest astropy/units
#
# You can then commit the changes to the re-generated _lextab.py and
# _parsetab.py files.
"""
Handles a "generic" string format for units
"""
import re
import unicodedata
import warnings
from fractions import Fraction
from astropy.utils import classproperty, parsing
from astropy.utils.misc import did_you_mean
from . import core, utils
from .base import Base
def _to_string(cls, unit):
if isinstance(unit, core.CompositeUnit):
parts = []
if cls._show_scale and unit.scale != 1:
parts.append(f"{unit.scale:g}")
if len(unit.bases):
positives, negatives = utils.get_grouped_by_powers(unit.bases, unit.powers)
if len(positives):
parts.append(cls._format_unit_list(positives))
elif len(parts) == 0:
parts.append("1")
if len(negatives):
parts.append("/")
unit_list = cls._format_unit_list(negatives)
if len(negatives) == 1:
parts.append(f"{unit_list}")
else:
parts.append(f"({unit_list})")
return " ".join(parts)
elif isinstance(unit, core.NamedUnit):
return cls._get_unit_name(unit)
[docs]class Generic(Base):
"""
A "generic" format.
The syntax of the format is based directly on the FITS standard,
but instead of only supporting the units that FITS knows about, it
supports any unit available in the `astropy.units` namespace.
"""
_show_scale = True
_tokens = (
"COMMA",
"DOUBLE_STAR",
"STAR",
"PERIOD",
"SOLIDUS",
"CARET",
"OPEN_PAREN",
"CLOSE_PAREN",
"FUNCNAME",
"UNIT",
"SIGN",
"UINT",
"UFLOAT",
)
@classproperty(lazy=True)
def _all_units(cls):
return cls._generate_unit_names()
@classproperty(lazy=True)
def _units(cls):
return cls._all_units[0]
@classproperty(lazy=True)
def _deprecated_units(cls):
return cls._all_units[1]
@classproperty(lazy=True)
def _functions(cls):
return cls._all_units[2]
@classproperty(lazy=True)
def _parser(cls):
return cls._make_parser()
@classproperty(lazy=True)
def _lexer(cls):
return cls._make_lexer()
@classmethod
def _make_lexer(cls):
tokens = cls._tokens
t_COMMA = r"\,"
t_STAR = r"\*"
t_PERIOD = r"\."
t_SOLIDUS = r"/"
t_DOUBLE_STAR = r"\*\*"
t_CARET = r"\^"
t_OPEN_PAREN = r"\("
t_CLOSE_PAREN = r"\)"
# NOTE THE ORDERING OF THESE RULES IS IMPORTANT!!
# Regular expression rules for simple tokens
def t_UFLOAT(t):
r"((\d+\.?\d*)|(\.\d+))([eE][+-]?\d+)?"
if not re.search(r"[eE\.]", t.value):
t.type = "UINT"
t.value = int(t.value)
elif t.value.endswith("."):
t.type = "UINT"
t.value = int(t.value[:-1])
else:
t.value = float(t.value)
return t
def t_UINT(t):
r"\d+"
t.value = int(t.value)
return t
def t_SIGN(t):
r"[+-](?=\d)"
t.value = int(t.value + "1")
return t
# This needs to be a function so we can force it to happen
# before t_UNIT
def t_FUNCNAME(t):
r"((sqrt)|(ln)|(exp)|(log)|(mag)|(dB)|(dex))(?=\ *\()"
return t
def t_UNIT(t):
"%|([YZEPTGMkhdcmu\N{MICRO SIGN}npfazy]?'((?!\\d)\\w)+')|((?!\\d)\\w)+"
t.value = cls._get_unit(t)
return t
t_ignore = " "
# Error handling rule
def t_error(t):
raise ValueError(f"Invalid character at col {t.lexpos}")
return parsing.lex(
lextab="generic_lextab", package="astropy/units", reflags=int(re.UNICODE)
)
@classmethod
def _make_parser(cls):
"""
The grammar here is based on the description in the `FITS
standard
<http://fits.gsfc.nasa.gov/standard30/fits_standard30aa.pdf>`_,
Section 4.3, which is not terribly precise. The exact grammar
is here is based on the YACC grammar in the `unity library
<https://bitbucket.org/nxg/unity/>`_.
This same grammar is used by the `"fits"` and `"vounit"`
formats, the only difference being the set of available unit
strings.
"""
tokens = cls._tokens
def p_main(p):
"""
main : unit
| structured_unit
| structured_subunit
"""
if isinstance(p[1], tuple):
# Unpack possible StructuredUnit inside a tuple, ie.,
# ignore any set of very outer parentheses.
p[0] = p[1][0]
else:
p[0] = p[1]
def p_structured_subunit(p):
"""
structured_subunit : OPEN_PAREN structured_unit CLOSE_PAREN
"""
# We hide a structured unit enclosed by parentheses inside
# a tuple, so that we can easily distinguish units like
# "(au, au/day), yr" from "au, au/day, yr".
p[0] = (p[2],)
def p_structured_unit(p):
"""
structured_unit : subunit COMMA
| subunit COMMA subunit
"""
from ..structured import StructuredUnit
inputs = (p[1],) if len(p) == 3 else (p[1], p[3])
units = ()
for subunit in inputs:
if isinstance(subunit, tuple):
# Structured unit that should be its own entry in the
# new StructuredUnit (was enclosed in parentheses).
units += subunit
elif isinstance(subunit, StructuredUnit):
# Structured unit whose entries should be
# individiually added to the new StructuredUnit.
units += subunit.values()
else:
# Regular unit to be added to the StructuredUnit.
units += (subunit,)
p[0] = StructuredUnit(units)
def p_subunit(p):
"""
subunit : unit
| structured_unit
| structured_subunit
"""
p[0] = p[1]
def p_unit(p):
"""
unit : product_of_units
| factor product_of_units
| factor product product_of_units
| division_product_of_units
| factor division_product_of_units
| factor product division_product_of_units
| inverse_unit
| factor inverse_unit
| factor product inverse_unit
| factor
"""
from astropy.units.core import Unit
if len(p) == 2:
p[0] = Unit(p[1])
elif len(p) == 3:
p[0] = Unit(p[1] * p[2])
elif len(p) == 4:
p[0] = Unit(p[1] * p[3])
def p_division_product_of_units(p):
"""
division_product_of_units : division_product_of_units division product_of_units
| product_of_units
"""
from astropy.units.core import Unit
if len(p) == 4:
p[0] = Unit(p[1] / p[3])
else:
p[0] = p[1]
def p_inverse_unit(p):
"""
inverse_unit : division unit_expression
"""
p[0] = p[2] ** -1
def p_factor(p):
"""
factor : factor_fits
| factor_float
| factor_int
"""
p[0] = p[1]
def p_factor_float(p):
"""
factor_float : signed_float
| signed_float UINT signed_int
| signed_float UINT power numeric_power
"""
if cls.name == "fits":
raise ValueError("Numeric factor not supported by FITS")
if len(p) == 4:
p[0] = p[1] * p[2] ** float(p[3])
elif len(p) == 5:
p[0] = p[1] * p[2] ** float(p[4])
elif len(p) == 2:
p[0] = p[1]
def p_factor_int(p):
"""
factor_int : UINT
| UINT signed_int
| UINT power numeric_power
| UINT UINT signed_int
| UINT UINT power numeric_power
"""
if cls.name == "fits":
raise ValueError("Numeric factor not supported by FITS")
if len(p) == 2:
p[0] = p[1]
elif len(p) == 3:
p[0] = p[1] ** float(p[2])
elif len(p) == 4:
if isinstance(p[2], int):
p[0] = p[1] * p[2] ** float(p[3])
else:
p[0] = p[1] ** float(p[3])
elif len(p) == 5:
p[0] = p[1] * p[2] ** p[4]
def p_factor_fits(p):
"""
factor_fits : UINT power OPEN_PAREN signed_int CLOSE_PAREN
| UINT power OPEN_PAREN UINT CLOSE_PAREN
| UINT power signed_int
| UINT power UINT
| UINT SIGN UINT
| UINT OPEN_PAREN signed_int CLOSE_PAREN
"""
if p[1] != 10:
if cls.name == "fits":
raise ValueError("Base must be 10")
else:
return
if len(p) == 4:
if p[2] in ("**", "^"):
p[0] = 10 ** p[3]
else:
p[0] = 10 ** (p[2] * p[3])
elif len(p) == 5:
p[0] = 10 ** p[3]
elif len(p) == 6:
p[0] = 10 ** p[4]
def p_product_of_units(p):
"""
product_of_units : unit_expression product product_of_units
| unit_expression product_of_units
| unit_expression
"""
if len(p) == 2:
p[0] = p[1]
elif len(p) == 3:
p[0] = p[1] * p[2]
else:
p[0] = p[1] * p[3]
def p_unit_expression(p):
"""
unit_expression : function
| unit_with_power
| OPEN_PAREN product_of_units CLOSE_PAREN
"""
if len(p) == 2:
p[0] = p[1]
else:
p[0] = p[2]
def p_unit_with_power(p):
"""
unit_with_power : UNIT power numeric_power
| UNIT numeric_power
| UNIT
"""
if len(p) == 2:
p[0] = p[1]
elif len(p) == 3:
p[0] = p[1] ** p[2]
else:
p[0] = p[1] ** p[3]
def p_numeric_power(p):
"""
numeric_power : sign UINT
| OPEN_PAREN paren_expr CLOSE_PAREN
"""
if len(p) == 3:
p[0] = p[1] * p[2]
elif len(p) == 4:
p[0] = p[2]
def p_paren_expr(p):
"""
paren_expr : sign UINT
| signed_float
| frac
"""
if len(p) == 3:
p[0] = p[1] * p[2]
else:
p[0] = p[1]
def p_frac(p):
"""
frac : sign UINT division sign UINT
"""
p[0] = Fraction(p[1] * p[2], p[4] * p[5])
def p_sign(p):
"""
sign : SIGN
|
"""
if len(p) == 2:
p[0] = p[1]
else:
p[0] = 1
def p_product(p):
"""
product : STAR
| PERIOD
"""
pass
def p_division(p):
"""
division : SOLIDUS
"""
pass
def p_power(p):
"""
power : DOUBLE_STAR
| CARET
"""
p[0] = p[1]
def p_signed_int(p):
"""
signed_int : SIGN UINT
"""
p[0] = p[1] * p[2]
def p_signed_float(p):
"""
signed_float : sign UINT
| sign UFLOAT
"""
p[0] = p[1] * p[2]
def p_function_name(p):
"""
function_name : FUNCNAME
"""
p[0] = p[1]
def p_function(p):
"""
function : function_name OPEN_PAREN main CLOSE_PAREN
"""
if p[1] == "sqrt":
p[0] = p[3] ** 0.5
return
elif p[1] in ("mag", "dB", "dex"):
function_unit = cls._parse_unit(p[1])
# In Generic, this is callable, but that does not have to
# be the case in subclasses (e.g., in VOUnit it is not).
if callable(function_unit):
p[0] = function_unit(p[3])
return
raise ValueError(f"'{p[1]}' is not a recognized function")
def p_error(p):
raise ValueError()
return parsing.yacc(tabmodule="generic_parsetab", package="astropy/units")
@classmethod
def _get_unit(cls, t):
try:
return cls._parse_unit(t.value)
except ValueError as e:
registry = core.get_current_unit_registry()
if t.value in registry.aliases:
return registry.aliases[t.value]
raise ValueError(f"At col {t.lexpos}, {str(e)}")
@classmethod
def _parse_unit(cls, s, detailed_exception=True):
registry = core.get_current_unit_registry().registry
if s in cls._unit_symbols:
s = cls._unit_symbols[s]
elif not s.isascii():
if s[0] == "\N{MICRO SIGN}":
s = "u" + s[1:]
if s[-1] in cls._prefixable_unit_symbols:
s = s[:-1] + cls._prefixable_unit_symbols[s[-1]]
elif len(s) > 1 and s[-1] in cls._unit_suffix_symbols:
s = s[:-1] + cls._unit_suffix_symbols[s[-1]]
elif s.endswith("R\N{INFINITY}"):
s = s[:-2] + "Ry"
if s in registry:
return registry[s]
if detailed_exception:
raise ValueError(f"{s} is not a valid unit. {did_you_mean(s, registry)}")
else:
raise ValueError()
_unit_symbols = {
"%": "percent",
"\N{PRIME}": "arcmin",
"\N{DOUBLE PRIME}": "arcsec",
"\N{MODIFIER LETTER SMALL H}": "hourangle",
"e\N{SUPERSCRIPT MINUS}": "electron",
}
_prefixable_unit_symbols = {
"\N{GREEK CAPITAL LETTER OMEGA}": "Ohm",
"\N{LATIN CAPITAL LETTER A WITH RING ABOVE}": "Angstrom",
"\N{SCRIPT SMALL L}": "l",
}
_unit_suffix_symbols = {
"\N{CIRCLED DOT OPERATOR}": "sun",
"\N{SUN}": "sun",
"\N{CIRCLED PLUS}": "earth",
"\N{EARTH}": "earth",
"\N{JUPITER}": "jupiter",
"\N{LATIN SUBSCRIPT SMALL LETTER E}": "_e",
"\N{LATIN SUBSCRIPT SMALL LETTER P}": "_p",
}
_translations = str.maketrans(
{
"\N{GREEK SMALL LETTER MU}": "\N{MICRO SIGN}",
"\N{MINUS SIGN}": "-",
}
)
"""Character translations that should be applied before parsing a string.
Note that this does explicitly *not* generally translate MICRO SIGN to u,
since then a string like 'µ' would be interpreted as unit mass.
"""
_superscripts = (
"\N{SUPERSCRIPT MINUS}"
"\N{SUPERSCRIPT PLUS SIGN}"
"\N{SUPERSCRIPT ZERO}"
"\N{SUPERSCRIPT ONE}"
"\N{SUPERSCRIPT TWO}"
"\N{SUPERSCRIPT THREE}"
"\N{SUPERSCRIPT FOUR}"
"\N{SUPERSCRIPT FIVE}"
"\N{SUPERSCRIPT SIX}"
"\N{SUPERSCRIPT SEVEN}"
"\N{SUPERSCRIPT EIGHT}"
"\N{SUPERSCRIPT NINE}"
)
_superscript_translations = str.maketrans(_superscripts, "-+0123456789")
_regex_superscript = re.compile(f"[{_superscripts}]?[{_superscripts[2:]}]+")
_regex_deg = re.compile("°([CF])?")
@classmethod
def _convert_superscript(cls, m):
return f"({m.group().translate(cls._superscript_translations)})"
@classmethod
def _convert_deg(cls, m):
if len(m.string) == 1:
return "deg"
return m.string.replace("°", "deg_")
[docs] @classmethod
def parse(cls, s, debug=False):
if not isinstance(s, str):
s = s.decode("ascii")
elif not s.isascii():
# common normalization of unicode strings to avoid
# having to deal with multiple representations of
# the same character. This normalizes to "composed" form
# and will e.g. convert OHM SIGN to GREEK CAPITAL LETTER OMEGA
s = unicodedata.normalize("NFC", s)
# Translate some basic unicode items that we'd like to support on
# input but are not standard.
s = s.translate(cls._translations)
# TODO: might the below be better done in the parser/lexer?
# Translate superscripts to parenthesized numbers; this ensures
# that mixes of superscripts and regular numbers fail.
s = cls._regex_superscript.sub(cls._convert_superscript, s)
# Translate possible degrees.
s = cls._regex_deg.sub(cls._convert_deg, s)
result = cls._do_parse(s, debug=debug)
# Check for excess solidi, but exclude fractional exponents (accepted)
n_slashes = s.count("/")
if n_slashes > 1 and (n_slashes - len(re.findall(r"\(\d+/\d+\)", s))) > 1:
warnings.warn(
"'{}' contains multiple slashes, which is "
"discouraged by the FITS standard".format(s),
core.UnitsWarning,
)
return result
@classmethod
def _do_parse(cls, s, debug=False):
try:
# This is a short circuit for the case where the string
# is just a single unit name
return cls._parse_unit(s, detailed_exception=False)
except ValueError as e:
try:
return cls._parser.parse(s, lexer=cls._lexer, debug=debug)
except ValueError as e:
if str(e):
raise
else:
raise ValueError(f"Syntax error parsing unit '{s}'")
@classmethod
def _get_unit_name(cls, unit):
return unit.get_format_name("generic")
@classmethod
def _format_unit_list(cls, units):
out = []
units.sort(key=lambda x: cls._get_unit_name(x[0]).lower())
for base, power in units:
if power == 1:
out.append(cls._get_unit_name(base))
else:
power = utils.format_power(power)
if "/" in power or "." in power:
out.append(f"{cls._get_unit_name(base)}({power})")
else:
out.append(f"{cls._get_unit_name(base)}{power}")
return " ".join(out)
[docs] @classmethod
def to_string(cls, unit):
return _to_string(cls, unit)
[docs]class Unscaled(Generic):
"""
A format that doesn't display the scale part of the unit, other
than that, it is identical to the `Generic` format.
This is used in some error messages where the scale is irrelevant.
"""
_show_scale = False