liberty/tools/asciiman.awk

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# asciiman.awk: simplified AsciiDoc to manual page converter
#
# Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
# SPDX-License-Identifier: 0BSD
#
# This is not intended to produce great output, merely useful output.
# As such, input documents should restrict themselves as follows:
#
# - In-line formatting sequences must not overlap,
# cannot be escaped, and cannot span lines.
# - Heading underlines must match in byte length exactly.
# - Only a small subset of syntax is supported overall.
#
# Also beware that the output has only been tested with GNU troff and mandoc.
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# Attributes can be passed via environment variables starting with "asciidoc-".
function fatal(message) {
print ".\\\" " FILENAME ":" FNR ": fatal error: " message
print FILENAME ":" FNR ": fatal error: " message > "/dev/stderr"
exit 1
}
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BEGIN {
for (name in ENVIRON)
if (match(name, /^asciidoc-/))
Attrs[substr(name, RSTART + RLENGTH)] = ENVIRON[name]
}
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function expand(s, attrname, v) {
while (match(s, /[{][^{}]+[}]/)) {
attrname = substr(s, RSTART + 1, RLENGTH - 2)
if (attrname in Attrs)
v = v substr(s, 1, RSTART - 1) Attrs[attrname]
else
v = v substr(s, 1, RSTART + RLENGTH - 1)
s = substr(s, RSTART + RLENGTH)
}
return v s
}
function escape(s) {
gsub(/\\/, "\\\\", s)
gsub(/-/, "\\-", s)
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sub(/^[.']/, "\\\\\\&&", s)
return s
}
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function readattribute(line, attrname) {
if (match(line, /^:[^:]+:$/)) {
Attrs[substr(line, RSTART + 1, RLENGTH - 2)] = ""
} else if (match(line, /^:[^:]+!:$/)) {
delete Attrs[substr(line, RSTART + 1, RLENGTH - 3)]
} else if (match(line, /^:![^:]+:$/)) {
delete Attrs[substr(line, RSTART + 2, RLENGTH - 3)]
} else if (match(line, /^:[^:]+: /)) {
attrname = substr(line, RSTART + 1, RLENGTH - 3)
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Attrs[attrname] = expand(substr(line, RSTART + RLENGTH))
} else {
return 0
}
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return 1
}
NR == 1 {
nameline = $0
if (match(nameline, /[(][[:digit:]][)]$/)) {
name = substr(nameline, 1, RSTART - 1)
section = substr(nameline, RSTART + 1, RLENGTH - 2)
} else {
fatal("invalid header line")
}
getline
if (length(nameline) != length($0) || /[^=]/)
fatal("invalid header underline")
getline
while (readattribute($0))
getline
if ($0)
fatal("expected an empty line after the header")
# Requesting tbl(1), even though we currently do not support tables.
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print "'\\\" t"
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printf ".TH \"%s\" \"%s\" \"\" \"%s\"",
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toupper(name), section, Attrs["mansource"]
if ("manmanual" in Attrs)
printf " \"%s\"", Attrs["manmanual"]
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print ""
# Hyphenation is indeed rather annoying, in particular with long links.
print ".nh"
}
function format(line, v) {
# Pass-through, otherwise useful for hacks, is a bit of a lie here,
# and formatting doesn't fully respect word boundaries.
while (line) {
if (match(line, /^[+][+][+][^+]+[+][+][+]/)) {
v = v substr(line, RSTART + 3, RLENGTH - 6)
} else if (match(line, /^__[^_]+__/)) {
v = v "\\fI" substr(line, RSTART + 2, RLENGTH - 4) "\\fP"
} else if (match(line, /^[*][*][^*]+[*][*]/)) {
v = v "\\fB" substr(line, RSTART + 2, RLENGTH - 4) "\\fP"
} else if (match(line, /^_[^_]+_/) &&
substr(line, RSTART + RLENGTH) !~ /^[[:alnum:]]/) {
v = v "\\fI" substr(line, RSTART + 1, RLENGTH - 2) "\\fP"
} else if (match(line, /^[*][^*]+[*]/) &&
substr(line, RSTART + RLENGTH) !~ /^[[:alnum:]]/) {
v = v "\\fB" substr(line, RSTART + 1, RLENGTH - 2) "\\fP"
} else {
v = v substr(line, 1, 1)
line = substr(line, 2)
continue
}
line = substr(line, RSTART + RLENGTH)
}
return v
}
function flushspace() {
if (NeedSpace) {
print ".sp"
NeedSpace = 0
}
}
function inline(line) {
if (!line) {
NeedSpace = 1
return
}
flushspace()
line = format(escape(expand(line)))
# Strip empty URL descriptions, otherwise useful for demarking the end.
while (match(line, /[^[:space:]]+\[\]/)) {
line = substr(line, 1, RSTART + RLENGTH - 3) \
substr(line, RSTART + RLENGTH)
}
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# Enable double-spacing after the end of a sentence.
gsub(/[.][[:space:]]+/, ".\n", line)
gsub(/[!][[:space:]]+/, "!\n", line)
gsub(/[?][[:space:]]+/, "?\n", line)
# Quote commands resulting from that, as well as from expand().
gsub(/\n[.]/, "\n\\\\\\&.", line)
gsub(/\n[']/, "\n\\\\\\&'", line)
sub(/[[:space:]]+[+]$/, "\n.br", line)
print line
}
# Returns 1 iff the left-over $0 should be processed further.
function process(firstline) {
if (readattribute(firstline))
return 0
if (getline <= 0) {
inline(firstline)
return 0
}
# mandoc(1) automatically precedes section headers with blank lines.
if (length(firstline) == length($0) && /^-+$/) {
print ".SH \"" escape(toupper(expand(firstline))) "\""
NeedSpace = 0
return 0
}
if (length(firstline) == length($0) && /^~+$/) {
print ".SS \"" escape(expand(firstline)) "\""
NeedSpace = 0
return 0
}
if (firstline ~ /^(-{4,}|[.]{4,})$/) {
flushspace()
print ".if n .RS 4"
print ".nf"
print ".fam C"
do {
print escape($0)
} while (getline > 0 && $0 != firstline)
print ".fam"
print ".fi"
print ".if n .RE"
return 0
}
if (firstline ~ /^\/{4,}$/) {
do {
print ".\\\" " $0
} while (getline > 0 && $0 != firstline)
return 0
}
if (match(firstline, /^\/\//)) {
print ".\\\"" substr(firstline, RSTART + RLENGTH)
return 1
}
# We generally assume these block end with a blank line.
if (match(firstline, /^[[:space:]]*[*][[:space:]]+/)) {
flushspace()
# Bullet magic copied over from AsciiDoc/Asciidoctor generators.
print ".RS 4"
print ".ie n \\{\\"
print "\\h'-04'\\(bu\\h'+03'\\c"
print ".\\}"
print ".el \\{\\"
print ".sp -1"
print ".IP \\(bu 2.3"
print ".\\}"
inline(substr(firstline, RSTART + RLENGTH))
while ($0) {
sub(/^[[:space:]]+/, "")
sub(/^[+]$/, "")
if (!process($0) && getline <= 0)
fatal("unexpected EOF")
if (match($0, /^[[:space:]]*[*][[:space:]]+/))
break
}
print ".RE"
NeedSpace = 1
return !!$0
}
if (match(firstline, /^[[:space:]]+/)) {
flushspace()
print ".if n .RS 4"
print ".nf"
print ".fam C"
do {
print escape(substr(firstline, RLENGTH + 1))
firstline = $0
} while ($0 && getline > 0)
print ".fam"
print ".fi"
print ".if n .RE"
return 1
}
if (match(firstline, /::$/)) {
inline(substr(firstline, 1, RSTART - 1))
while (match($0, /::$/)) {
print ".br"
inline(substr($0, 1, RSTART - 1))
if (getline <= 0)
fatal("unexpected EOF")
}
print ".RS 4"
while ($0) {
sub(/^[[:space:]]+/, "")
sub(/^[+]$/, "")
if (!process($0) && getline <= 0)
fatal("unexpected EOF")
if (match($0, /::$/))
break
}
print ".RE"
NeedSpace = 1
return !!$0
}
inline(firstline)
return 1
}
{
while (process($0)) {}
}