From: Eric S. Raymond <esr@thyrsus.com>
Date: Mon, 9 Oct 2006 23:14:11 +0000 (+0000)
Subject: Two sources of vast confusion in reading the C code are these:
X-Git-Tag: 2.0~107
X-Git-Url: https://jxself.org/git/?p=super-star-trek.git;a=commitdiff_plain;h=e67cf36a789c4ab1cd905a9a08e91d219395f538;hp=e67cf36a789c4ab1cd905a9a08e91d219395f538

Two sources of vast confusion in reading the C code are these:

(1) the code uses x and y as though they're Cartesian coordinate
variables, but (inconsistently) swaps them around so that "x"
variables usually refer to the y direction in the output charts.

(2) Coordinates in the y direction (whether they are x variables or
not) increase *downwards* (charts are printed row zero first).

There is extremely ugly and confusing code in targetcheck() and
getcourse() where two opposite sets of conventions bump up against
each other.

As a first step, towards untangling this mess, we'll change the
nomenclature so that coordinate names refer to 'i' and 'j'
directions, as in matrix indices (i vertical, increasing downwards,
and j horizontal, increasing rightwards).  This patch does that for
the coord class members, also fixing two small bugs that turned
up during testing.

More steps will be necessary...
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