# A library of GAWK functions for removing
# easily confused details from EVA text.
# Last edited on 1999-02-01 00:07:27 by stolfi
# ========================================================================
# Functions for erasing comments:
function erg_erase_string(str)
{
# Returns a string of "!"s with same length as "str".
return gensub(/./, "!", "g", str);
}
function erg_erase_comments(old, new, i)
{
# Removes '{}' comments and other fillers from "old",
# replacing them by "!"s so as to preserve the length.
new = "";
while (length(old) != 0)
{ i = index(old, "{");
if (i == 0)
{ new = (new old); old = ""; }
else if (i > 1)
{ new = (new substr(old, 1, i-1));
old = substr(old, i);
}
else
{ match(old, /^{[^{}]*}/);
if (RSTART > 0)
{ new = (new erg_erase_string(substr(old, 1, RLENGTH)));
old = substr(old, RLENGTH + 1);
}
else
{ printf "line %d, bad {}-comment\n", NR > "/dev/stderr";
new = (new old); old = "";
}
}
}
return new;
}
# ========================================================================
# Functions for finding similar words:
#
# The following recoding operations may map two or more EVA
# characters to a fewer number of characters. In that case
# the balance is filled with " ", not "!", for the
# benefit of erg_char_offsets below.
#
# These functions should be applied in the order in which they
# are declared here.
function erg_map_ee_to_ch(txt)
{
# Maps "ee" to "ch" and "se" to "sh", i.e. provides a ligature.
gsub(/se/, "sh", txt);
gsub(/ee/, "ch", txt);
return txt
}
function erg_map_sh_to_ch(txt)
{
# Maps "sh" to "ch", i.e. erases the plume on "sh" (but not on "s").
gsub(/sh/, "ch", txt);
return txt
}
function erg_erase_ligatures(txt)
{
# Erases the ligature information, namely the
# difference between "sh" and "se", "ch" and "ee",
# "ckh" and "eke", etc.
gsub(/c/, "e", txt);
gsub(/h/, "e", txt);
return txt
}
function erg_erase_plumes(txt)
{
# Erases the plume on "s", "r", by converting them to "e".
# Also erases the isolated plumes ['"+].
# Also converts "sh" to "ch", if it has not been
# eliminated by erg_erase_ligatures or erg_map_sh_to_ch.
# Also maps "u" to "a".
# Does not affect "n".
gsub(/sh/, "ch", txt);
gsub(/s/, "e", txt);
gsub(/r/, "e", txt);
gsub(/u/, "a", txt);
txt = gensub(/([oayechi])['"+]/, "\\1 ", "g", txt);
return txt
}
function erg_ignore_gallows_eyes(txt)
{
# Erases the "eye" information from all gallows,
# by mapping "k" to "t" and "f" to "p".
gsub(/k/, "t", txt);
gsub(/f/, "p", txt);
return txt
}
function erg_join_ei(txt)
{
# Collapses "ei" to "a".
gsub(/ei/, "a ", txt);
return txt
}
function erg_equate_aoy(txt)
{
# Erases the differences between "a", "o", "y",
# mapping them all to "o".
gsub(/a/, "o", txt);
gsub(/y/, "o", txt);
return txt
}
function erg_equate_bn(txt)
{
# Maps "b" to "n".
gsub(/b/, "n", txt);
return txt
}
function erg_collapse_ii(txt)
{
# Maps "ii" and "iii" and "iiii" to just "i".
gsub(/iiii/, "i ", txt);
gsub(/iii/, "i ", txt);
gsub(/ii/, "i ", txt);
return txt
}
function erg_equate_eights(txt)
{
# Identifies "j", "g", "m" with "d".
gsub(/j/, "d", txt);
gsub(/g/, "d", txt);
gsub(/m/, "d", txt);
return txt
}
function erg_equate_pt(txt)
{
# Identifies "p" with "t".
gsub(/p/, "t", txt);
return txt
}
function erg_erase_q(txt)
{
# Replaces "qX" by "X ", in a chunk of comment-free EVA.
# Adds a space after the letter to preserve length.
# Note that the space comes after to ensure we compute the correct offsets.
# Better call "erg_join_ei" before this one.
return gensub(/q([oayeclktp])/, "\\1 ", "g", txt);
}
# ========================================================================
# Functions for dealing with word spaces:
# These functions consider "/" a space, too.
function erg_unify_word_spaces(str)
{
# Replaces all EVA word spaces by "."s
return gensub(/[-/=,.]/, ".", "g", str);
}
function erg_erase_word_spaces(str)
{
# Replaces all EVA word spaces by "!"s
return gensub(/[-/=,.]/, "!", "g", str);
}
# ========================================================================
# Functions for discarding words that contain invalid characters:
function erg_crush_invalid_words(str, res)
{
# Replaces any word that contains an invalid character by "*"s
res = "";
while (str != "")
{ if (match(str, /^[^*?%]*([-.,/=]+|$)/))
{ res = (res substr(str, 1, RLENGTH));
str = substr(str,RLENGTH+1);
}
else if (match(str, /^[^-.,/=]*[?*%][^-.,/=]*/))
{ res = (res "?" erg_erase_string(substr(str, RLENGTH-1)));
str = substr(str,RLENGTH+1);
}
else
{ printf "line %d, erg_crush_invalid_words lost\n", NR > "/dev/stderr";
abort = 1; exit 1;
}
}
return res
}
# ========================================================================
# Functions for squeezing out fillers (and remembering them):
function erg_pack(old)
{
# Removes all fillers from "old"
return gensub(/[!% ]/, "", "g", old);
}
function erg_char_offsets(txt, iof, fof, i, k, m, c, goon)
{
# Expects iof and bof to be empty arrays. Stores in iof[i] the byte
# offset of the substring of txt that apparently gave rise to the
# ith character of the string pck = erg_pack(txt). Also stores in
# fof[i] the byte offset for the end of that string.
#
# Assumes that the string of a non-filler character includes
# that character and any succeeding " "s. Thus
#
# E.g. suppose txt = "!!!ab !c !" so that pck = "abc"; then
# iof[1..3] will be {3,4,7} and fof[1..3] will be {4,6,10}.
# Also sets fof[0] to 0 and iof[length(pck)] to length(txt).
i = 0; m = length(txt);
fof[i] = 0; goon = 0;
for(k=1;k<=m;k++)
{ c = substr(txt,k,1);
if ((c == "!") || (c == "%"))
{ goon = 0; }
else if (c == " ")
{ if (goon) fof[i] = k; }
else
{ i++; iof[i] = k-1; fof[i] = k; goon = 1; }
}
iof[i + 1] = m;
}