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Python Regrets OSCON, July 25, 2002

Python Regrets OSCON, July 25, 2002. Guido van Rossum Director of PythonLabs at Zope Corporation guido@zope.com guido@python.org. Relics. Stuff that’s already being phased out string exceptions sys.exc_type etc. (use sys.exc_info()) int/int returning int apply() (use f(*args, **kwds))

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Python Regrets OSCON, July 25, 2002

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  1. Python RegretsOSCON, July 25, 2002 Guido van Rossum Director of PythonLabs at Zope Corporation guido@zope.comguido@python.org

  2. Relics • Stuff that’s already being phased out • string exceptions • sys.exc_type etc. (use sys.exc_info()) • int/int returning int • apply() (use f(*args, **kwds)) • coerce() (no longer needed) • 3-way compare? (but... comparing lists)

  3. Lexical details • continued lines or strings with \ • use (...) continuation and/or string literal concatenation • if expression: statement • put statement on next line • tabs? • require all spaces • or very restricted use of tabs (not mixed)

  4. Lambda and functional stuff • I've never liked lambda • crippled (only one expression) • confusing (no argument list parentheses) • can use a local function instead • map(), filter() • using a Python function here is slow • list comprehensions do the same thing better • reduce() • nobody uses it, few understand it • a for loop is clearer & (usually) faster

  5. print, str() and repr() • drop `x` for repr(x) • ` is hard to read in many fonts • publication process turns 's' into ‘s’ • do we really need both str() and repr()? • mostly intended to be able to special-case"print x" when x is a string • still not enough; need nice() that's a bybrid • print should've been a function • write(x, y, z) • writeln(x, y, z) • spaces between items controlled by keyword arg

  6. Builtins • intern(), id(): put in sys • xrange(): make range() return an iterator • buffer(): must die (use bytes, PEP 296) • raw_input(): use sys.stdin.readline() • input(): use eval(sys.stdin.readline()) • callable(): just call it, already • execfile(), reload(): use exec() • compile(): put in sys

  7. Special cases for exec • exec as a statement is not worth it • make it a function (again :-) • perhaps shouldn't have locals(), globals(), vars()

  8. Restricted execution • Too many bugs to be trusted • didn't get enough review, and never will • Confusion btw. __builtins__, __builtin__ • But there's a useful idea somewhere... • Zope uses this

  9. Float to int conversion • need more ways to convert float to int (round, truncate-towards-zero, floor, ceil) • need differentiate to __int__ which truncates and __int__ which doesn't

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