doc: Build keywords multitable automatically

Keywords are now listed in a plain text file. They're sorted in
column-major order and rendered as a texinfo multitable in rust.texi.

Fixes issue #1216.

doc/keywords.txt

@@ -0,0 +1,20 @@
+## Add Rust keywords here. Lines start with '#' are ignored
+
+alt any as assert
+be bind block bool break
+char check claim const cont
+do
+else export
+f32 f64 fail false float fn for
+i16 i32 i64 i8 if import in int
+lambda let log
+mod mutable
+native note
+obj  
+prove pure
+resource ret
+self str syntax
+tag true type
+u16 u32 u64 u8 uint unchecked unsafe use
+vec
+when while with

doc/rust.texi

@@ -615,72 +615,7 @@ The keywords are:
 
 @sp 2
 
-@multitable @columnfractions .15 .15 .15 .15 .15
-@item @code{alt}
-@tab @code{const}
-@tab @code{i32}
-@tab @code{note}
-@tab @code{u32}
-@item @code{any}
-@tab @code{cont}
-@tab @code{i64}
-@tab @code{obj}
-@tab @code{u64}
-@item @code{as}
-@tab @code{do}
-@tab @code{i8}
-@tab @code{prove}
-@tab @code{u8}
-@item @code{assert}
-@tab @code{else}
-@tab @code{if}
-@tab @code{pure}
-@tab @code{uint}
-@item @code{}
-@tab @code{export}
-@tab @code{import}
-@tab @code{resource}
-@tab @code{unchecked}
-@item @code{be}
-@tab @code{f32}
-@tab @code{in}
-@tab @code{ret}
-@tab @code{unsafe}
-@item @code{bind}
-@tab @code{f64}
-@tab @code{int}
-@tab @code{self}
-@tab @code{use}
-@item @code{block}
-@tab @code{fail}
-@tab @code{lambda}
-@tab @code{str}
-@tab @code{vec}
-@item @code{bool}
-@tab @code{false}
-@tab @code{let}
-@tab @code{syntax}
-@tab @code{when}
-@item @code{break}
-@tab @code{float}
-@tab @code{log}
-@tab @code{tag}
-@tab @code{while}
-@item @code{char}
-@tab @code{fn}
-@tab @code{mod}
-@tab @code{true}
-@tab @code{with}
-@item @code{check}
-@tab @code{for}
-@tab @code{mutable}
-@tab @code{type}
-@tab @code{}
-@item @code{claim}
-@tab @code{i16}
-@tab @code{native}
-@tab @code{u16}
-@end multitable
+@include keywords.texi
 
 @node       Ref.Lex.Res
 @subsection Ref.Lex.Res

mk/docs.mk

@@ -4,20 +4,24 @@
 
 docs: $(DOCS)
 
+doc/keywords.texi: $(S)doc/keywords.txt $(S)src/etc/gen-keywords-table.py
+	@$(call E, gen-keywords-table: $@)
+	$(Q)$(S)src/etc/gen-keywords-table.py
+
 doc/version.texi: $(MKFILES) rust.texi
 	@$(call E, version-stamp: $@)
 	$(Q)echo "@macro gitversion" >$@
 	$(Q)echo "$(CFG_VERSION)" >>$@
 	$(Q)echo "@end macro" >>$@
 
-doc/%.pdf: %.texi doc/version.texi
+doc/%.pdf: %.texi doc/version.texi doc/keywords.texi
 	@$(call E, texi2pdf: $@)
 	@# LC_COLLATE=C works around a bug in texi2dvi; see
 	@# https://bugzilla.redhat.com/show_bug.cgi?id=583011 and
 	@# https://github.com/graydon/rust/issues/1134
 	$(Q)LC_COLLATE=C texi2pdf --silent --batch -I doc -o $@ --clean $<
 
-doc/%.html: %.texi doc/version.texi
+doc/%.html: %.texi doc/version.texi doc/keywords.texi
 	@$(call E, makeinfo: $@)
 	$(Q)makeinfo -I doc --html --ifhtml --force --no-split --output=$@ $<
 

src/etc/gen-keywords-table.py

@@ -0,0 +1,103 @@
+#!/usr/bin/env python
+
+import sys
+import os.path
+
+def scrub(b):
+  if sys.version_info >= (3,) and type(b) == bytes:
+    return b.decode('ascii')
+  else:
+    return b
+
+src_dir = scrub(os.getenv("CFG_SRC_DIR"))
+if not src_dir:
+  raise Exception("missing env var CFG_SRC_DIR")
+
+
+def get_keywords():
+  keywords_file = os.path.join(src_dir, "doc", "keywords.txt")
+  keywords = []
+  for line in open(keywords_file).readlines():
+    if not line or line.startswith('#'):
+      continue
+    for kw in line.split():
+      if kw.isalnum():
+        keywords.append(kw)
+  return keywords
+
+
+def sort(keywords, ncols):
+  """Sort keywords in a column-major ordered table.
+
+  Args:
+    keywords: List of keywords
+    ncols: Number of columns to be sorted
+  """
+  ## sort and remove duplicates
+  keywords = sorted(list(set(keywords)))
+  sz = len(keywords)
+
+  if sz % ncols > 0:
+    nrows = sz / ncols + 1
+  else:
+    nrows = sz / ncols
+
+  result = []
+  max = ncols * nrows
+  for i in xrange(0, max):
+    result.append("")
+
+  for i in xrange(1, sz+1):
+    if i % nrows == 0:
+      extra = 0
+    else:
+      extra = 1
+    pos = (((i + (nrows - 1)) % nrows) * ncols) + \
+          (i / nrows + extra)
+    result[pos - 1] = keywords[i - 1]
+
+  return rows(result, ncols)
+
+
+def rows(keywords, ncols):
+  """Split input list of keywords into rows.
+
+  Each contains ncols or ncols-1 elements.
+
+  Args:
+    keywords: List of keywords sorted in column-major order
+    ncols: Number of columns
+  """
+  sz = len(keywords)
+  result = []
+  i = 0
+  while i < sz:
+    if i + ncols < sz:
+      se = i + ncols
+    else:
+      se = sz
+    result.append(keywords[i:se])
+    i = se
+  return result
+
+
+def table(rows):
+  """Render rows in a texinfo multitable."""
+  result = ["@multitable @columnfractions .15 .15 .15 .15 .15\n"]
+  for row in rows:
+    result += ["@item @code{" + row[0] + "}\n"];
+    for e in row[1:]:
+      result += ["@tab @code{" + e + "}\n"];
+  result += ["@end multitable\n"];
+  return result
+
+
+def main(oargs):
+  keywords = get_keywords()
+  out_file = open(os.path.join("doc", "keywords.texi"), 'w')
+  for line in table(sort(keywords, 5)):
+    out_file.write(line)
+  out_file.close()
+
+if __name__ == '__main__':
+  main(sys.argv[1:])