fix: move BRF Python script to scripts/build-brf.py to avoid YAML issues

Heredoc with backslashes/quotes in YAML breaks parsing. Move the
python3-louis braille translation to scripts/build-brf.py and call it
from the workflow step.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: taylorarndt

.github/workflows/build-epub.yml

@@ -41,42 +41,8 @@ jobs:
         continue-on-error: true
         run: |
           mkdir -p epub/brf
-          # Pandoc extracts plain text from EPUB
           pandoc epub/git-going-with-github.epub -f epub -t plain -o /tmp/book.txt
-          # Python + liblouis translates text → Grade 2 braille → NABCC ASCII BRF (no TTS, pure text)
-          python3 - <<'EOF'
-import louis, sys
-
-NABCC = ' A1B\'K2L@CIF/MSP"E3H9O6R^DJG>NTQ,*5<-U8V.%[$+X!&;:4\\0Z7(_?W]#Y)='
-
-def to_brf(ub):
-    out = []
-    for ch in ub:
-        c = ord(ch)
-        if 0x2800 <= c <= 0x283F:
-            out.append(NABCC[c - 0x2800])
-        else:
-            out.append(ch if c < 128 else ' ')
-    return ''.join(out)
-
-with open('/tmp/book.txt', encoding='utf-8', errors='replace') as f:
-    lines = f.read().split('\n')
-
-brf = []
-for line in lines:
-    if line.strip():
-        try:
-            brf.append(to_brf(louis.translateString(['en-ueb-g2.ctb'], line)))
-        except Exception:
-            brf.append(line[:80])
-    else:
-        brf.append('')
-
-out = '\n'.join(brf)
-with open('epub/brf/git-going-with-github.brf', 'w', encoding='ascii', errors='replace') as f:
-    f.write(out)
-print(f"BRF written: {len(out)} bytes, {len(brf)} lines")
-EOF
+          python3 scripts/build-brf.py /tmp/book.txt epub/brf/git-going-with-github.brf
           ls -lh epub/brf/
 
       - name: Upload EPUB artifact

scripts/build-brf.py

@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+"""
+Convert plain text to BRF (Braille Ready Format) using liblouis.
+No TTS required — this is pure text-to-braille-dots translation.
+
+Usage: python3 build-brf.py input.txt output.brf
+"""
+import sys
+import louis
+
+# NABCC (North American Braille Computer Code) lookup table.
+# Maps 6-dot braille cell bitmask (0-63) to ASCII character.
+# bit 0=dot1, bit1=dot2, bit2=dot3, bit3=dot4, bit4=dot5, bit5=dot6
+NABCC = " A1B'K2L@CIF/MSP\"E3H9O6R^DJG>NTQ,*5<-U8V.%[$+X!&;:4\\0Z7(_?W]#Y)="
+
+
+def unicode_braille_to_brf(text):
+    """Convert Unicode braille characters (U+2800-U+283F) to NABCC ASCII."""
+    out = []
+    for ch in text:
+        code = ord(ch)
+        if 0x2800 <= code <= 0x283F:
+            out.append(NABCC[code - 0x2800])
+        elif code < 128:
+            out.append(ch)
+        else:
+            out.append(" ")
+    return "".join(out)
+
+
+def main():
+    input_file = sys.argv[1] if len(sys.argv) > 1 else "/tmp/book.txt"
+    output_file = sys.argv[2] if len(sys.argv) > 2 else "output.brf"
+
+    with open(input_file, encoding="utf-8", errors="replace") as f:
+        lines = f.read().split("\n")
+
+    brf_lines = []
+    for line in lines:
+        if line.strip():
+            try:
+                braille = louis.translateString(["en-ueb-g2.ctb"], line)
+                brf_lines.append(unicode_braille_to_brf(braille))
+            except Exception:
+                brf_lines.append(line[:80])
+        else:
+            brf_lines.append("")
+
+    output = "\n".join(brf_lines)
+    with open(output_file, "w", encoding="ascii", errors="replace") as f:
+        f.write(output)
+
+    print(f"BRF written: {len(output):,} bytes, {len(brf_lines):,} lines")
+
+
+if __name__ == "__main__":
+    main()