\begin{funcdesc}{context_diff}{a, b\optional{, fromfile\optional{, tofile

\optional{, fromfiledate\optional{, tofiledate\optional{, n

\optional{, lineterm}}}}}}}

Compare \var{a} and \var{b} (lists of strings); return a

delta (a generator generating the delta lines) in context diff

format.

Context diffs are a compact way of showing just the lines that have

changed plus a few lines of context. The changes are shown in a

before/after style. The number of context lines is set by \var{n}

which defaults to three.

By default, the diff control lines (those with \code{***} or \code{---})

are created with a trailing newline. This is helpful so that inputs created

from \function{file.readlines()} result in diffs that are suitable for use

with \function{file.writelines()} since both the inputs and outputs have

trailing newlines.

For inputs that do not have trailing newlines, set the \var{lineterm}

argument to \code{""} so that the output will be uniformly newline free.

The context diff format normally has a header for filenames and

modification times. Any or all of these may be specified using strings for

\var{fromfile}, \var{tofile}, \var{fromfiledate}, and \var{tofiledate}.

The modification times are normally expressed in the format returned by

\function{time.ctime()}. If not specified, the strings default to blanks.

\file{Tools/scripts/diff.py} is a command-line front-end for this

function.

\end{funcdesc}

\begin{funcdesc}{unified_diff}{a, b\optional{, fromfile\optional{, tofile

\optional{, fromfiledate\optional{, tofiledate\optional{, n

\optional{, lineterm}}}}}}}

Compare \var{a} and \var{b} (lists of strings); return a

delta (a generator generating the delta lines) in unified diff

format.

Unified diffs are a compact way of showing just the lines that have

changed plus a few lines of context. The changes are shown in a

inline style (instead of separate before/after blocks). The number

of context lines is set by \var{n} which defaults to three.

By default, the diff control lines (those with \code{---}, \code{+++},

or \code{@@}) are created with a trailing newline. This is helpful so

that inputs created from \function{file.readlines()} result in diffs

that are suitable for use with \function{file.writelines()} since both

the inputs and outputs have trailing newlines.

For inputs that do not have trailing newlines, set the \var{lineterm}

argument to \code{""} so that the output will be uniformly newline free.

The context diff format normally has a header for filenames and

modification times. Any or all of these may be specified using strings for

\var{fromfile}, \var{tofile}, \var{fromfiledate}, and \var{tofiledate}.

The modification times are normally expressed in the format returned by

\function{time.ctime()}. If not specified, the strings default to blanks.

\file{Tools/scripts/diff.py} is a command-line front-end for this

function.

\end{funcdesc}