1 files changed, 168 insertions, 0 deletions

@@ -0,0 +1,168 @@
+#!/usr/bin/awk -f
+# -*- indent-tabs-mode: t; -*-
+# HAT TRICK
+# (C) 2022 C. Duckworth
+
+### Commentary:
+
+### Code:
+BEGIN {
+        split("html,gemini,gopher", HT_FORMATS_AVAILABLE, ",")
+        process_arguments()
+        normalize_ht_formats()
+        if (! HT_TAGCHARS[1]) {
+                split("b:**,i://,code:``", HT_TAGCHARS, ",")
+        }
+        # Output buffer.  The output will be chunked into blocks.
+        BUFFER = ""
+        # The current block type.  We start with a standard paragraph.
+        BLOCK = "p"
+}
+
+### RAW TEXT
+/^>>>/ {
+}
+
+/^<<</ {
+}
+
+### BLOCKS
+/^#+/ {                 # Headers
+}
+
+/^>/ {                          # Block quote
+}
+
+/^-/ {                          # Unordered list
+}
+
+/^[0-9]\./ {                    # Ordered list
+}
+
+/^---$/ {                       # Section break
+}
+
+### LINES
+/^=>/ {                 # Link
+}
+
+/^</ {                          # HTML tag
+}
+
+/^;/ {                          # Comment
+}
+
+### EVERYTHING ELSE
+{
+}
+
+### FINISH
+END {
+        buflush()
+}
+
+### FUNCTIONS
+function buflush()
+{
+        # Print the buffer and close the current block.
+        if (BUFFER) {
+                ht_print(BUFFER)
+        }
+        BUFFER = ""
+        if ("html" in HT_FORMATS && BLOCK != "raw") {
+                ht_print("</" BLOCK ">")
+        }
+        print
+}
+
+function bufpush(str)
+{
+        # Push STR onto the buffer after a newline.
+        BUFFER = BUFFER (BUFFER ? "\n" : "") str
+}
+
+function ht_print(str)
+{
+        if (HT_FORMATS_COUNT == 1) {
+                print str
+        } else {
+                split(str, arr, "\n")
+                for (format in HT_FORMATS) {
+                        line = 1
+                        while (arr[line]) {
+                                printf "%s\t%s\n", format, arr[line++]
+                        }
+                }
+        }
+}
+
+function html_escape(str)
+{
+        # Escape HTML entities and beginning-line spaces.
+        gsub(/&/, "\\&amp;", t)
+        gsub(/</, "\\&lt;", t)
+        gsub(/>/, "\\&gt;", t)
+        sub(/^ /, "\\&nbsp;", t)
+        return t
+}
+
+function normalize_ht_formats()
+{
+        for (format in HT_FORMATS_AVAILABLE) {
+                normat[format] = 0
+        }
+        if (! HT_FORMATS[1]) {
+                for (i in HT_FORMATS_AVAILABLE) {
+                        HT_FORMATS[i] = HT_FORMATS_AVAILABLE[i]
+                }
+        }
+        for (format in HT_FORMATS) {
+                if (format == "all") {
+                        for (i in HT_FORMATS_AVAILABLE) {
+                                HT_FORMATS[i] = HT_FORMATS_AVAILABLE[i]
+                        }
+                        return
+                } else if (format ~ /^-/) {
+                        delete normat[substr(format, 2)]
+                } else {
+                        normat[format] = 1
+                }
+        }
+        for (format in normat) {
+                if (normat[format]) {
+                        HT_FORMATS[format] = format
+                }
+        }
+        for (format in HT_FORMATS) {
+                HT_FORMATS_COUNT++
+        }
+}
+
+function process_arguments()
+{
+        a = 1
+        HT_FORMATS[1] = 0
+        HT_TAGCHARS[1] = 0
+        while (ARGV[a]) {
+                if (a == "-c" || a ~ /^--chars=/) {
+                        # HTML tag <-> markup character correspondance
+                        if (a == "-c") {
+                                a++
+                        } else if (a ~ /^--chars=/) {
+                                sub(/^[^=]*=/, "", a)
+                                # HT_TAGCHARS is an array
+                        }
+                        split(a, HT_TAGCHARS, ",")
+                } else if (a == "-f" || a ~ /^--format=/) {
+                        # Output format
+                        if (a == "-f") {
+                                a++
+                        } else if (a ~ /^--format=/) {
+                                sub(/^[^=]*=/, "", a)
+                                # HT_FORMATS is an array
+                        }
+                        split(a, HT_FORMATS, ",")
+                }
+                a++
+        }
+}