doc: Translate extract-tests.js to python

doc/extract-tests.py

@@ -0,0 +1,55 @@
+# Script for extracting compilable fragments from markdown
+# documentation. See prep.js for a description of the format
+# recognized by this tool. Expects a directory fragements/ to exist
+# under the current directory, and writes the fragments in there as
+# individual .rs files.
+
+import sys, re;
+
+if len(sys.argv) < 2:
+    print("Please provide an input filename")
+    sys.exit(1)
+
+filename = sys.argv[1]
+f = open(filename)
+lines = f.readlines()
+f.close()
+
+cur = 0
+line = ""
+chapter = ""
+chapter_n = 0
+
+while cur < len(lines):
+    line = lines[cur]
+    cur += 1
+    chap = re.match("# (.*)", line);
+    if chap:
+        chapter = re.sub(r"\W", "_", chap.group(1)).lower()
+        chapter_n = 1
+    elif re.match("~~~", line):
+        block = ""
+        ignore = False
+        while cur < len(lines):
+            line = lines[cur]
+            cur += 1
+            if re.match(r"\s*## (notrust|ignore)", line):
+                ignore = True
+            elif re.match("~~~", line):
+                break
+            else:
+                block += re.sub("^# ", "", line)
+        if not ignore:
+            if not re.search(r"\bfn main\b", block):
+                if re.search(r"(^|\n) *(native|use|mod|import|export)\b", block):
+                    block += "\nfn main() {}\n"
+                else:
+                    block = "fn main() {\n" + block + "\n}\n"
+            if not re.search(r"\buse std\b", block):
+                block = "use std;\n" + block;
+            filename = "fragments/" + str(chapter) + "_" + str(chapter_n) + ".rs"
+            chapter_n += 1
+            f = open(filename, 'w')
+            f.write(block)
+            f.close()
+