From ace2fe485cc46c67fc425a6c4632f2a1ce606c88 Mon Sep 17 00:00:00 2001 From: bnewbold Date: Tue, 5 Apr 2016 12:29:23 -0400 Subject: document dot/underline difficulties with objects --- HACKING | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 HACKING (limited to 'HACKING') diff --git a/HACKING b/HACKING new file mode 100644 index 0000000..8e32954 --- /dev/null +++ b/HACKING @@ -0,0 +1,48 @@ + +### Problems With Python/Julia Syntax Mapping with dot ('.') Operator + +*aka, why the annoying underscore syntax is needed* + +Using PyCall, we can map python modules to Julia modules with the same syntax: + + python> import os + python> os.uname() + python> os.O_RDONLY + + julia> using PyCall + julia> os = pywrap(pyimport("os")) + julia> os.uname() + julia> os.O_RDONLY + +And using a recursive version of pywrap (`pyrecwrap`), we can get nested +modules to map also: + + python> import os + python> os.path.genericpath.os.uname() + + julia> os = pyrecwrap(pyimport("os")) + julia> os.path.genericpath.os.uname() + +We can also map python classes to Julia modules: + + python> import pyx.style.linewidth as psl + python> psl.THICK + + julia> ps = pywrap(pyimport("pyx.style")) + julia> psl = pywrap(ps.linewidth) + julia> psl.THICK + +However, in Python a class/object can both have members and be called as an +initializer: + + python> psl.THIN + python> psl(0.1) + +But in Julia a Module can't act as a function. + +Thus, a one-to-one syntax mapping just isn't going to work until (unless?) the +dot ('.') operator can be overridden (as of Julia 0.4 it may not). + +The work around used in this project (PyX.jl) is to use underscores in +object/function names and dots in object/module names. Eg, +`style.linewidth(0.2)` vs. `style_linewidth.THICK`. -- cgit v1.2.3