Add new build tool.

bibliogra.py requires Python 2, which is a pain to deal with.  This
commit adds a Go tool that compiles CensorBib from BibTeX to HTML.  The
tool does the bare minimum and is quite strict in the BibTeX format it
expects.

src/main.go

@@ -0,0 +1,113 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"regexp"
+	"strings"
+
+	"github.com/nickng/bibtex"
+)
+
+// Matches e.g.: @inproceedings{Doe2024a,
+var re = regexp.MustCompile(`@[a-z]*\{([A-Za-z\-]*[0-9]{4}[a-z]),`)
+
+// Map a cite name (e.g., Doe2024a) to its line number in the .bib file. All
+// cite names are unique.
+type entryToLineFunc func(string) int
+
+// Augment bibtex.BibEntry with the entry's line number in the .bib file.
+type bibEntry struct {
+	bibtex.BibEntry
+	lineNum int
+}
+
+func toStr(b bibtex.BibString) string {
+	if b == nil {
+		return ""
+	}
+	return b.String()
+}
+
+func parseBibFile(path string) []bibEntry {
+	file, err := os.Open(path)
+	if err != nil {
+		log.Fatal(err)
+	}
+	bib, err := bibtex.Parse(file)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Augment our BibTeX entries with their respective line numbers in the .bib
+	// file. This is necessary to create the "Download BibTeX" links.
+	lineOf := buildEntryToLineFunc(path)
+	bibEntries := []bibEntry{}
+	for _, entry := range bib.Entries {
+		bibEntries = append(bibEntries, bibEntry{
+			BibEntry: *entry,
+			lineNum:  lineOf(entry.CiteName),
+		})
+	}
+
+	return bibEntries
+}
+
+func buildEntryToLineFunc(path string) entryToLineFunc {
+	file, err := os.Open(path)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	sc := bufio.NewScanner(file)
+	entryToLine := make(map[string]int)
+	line := 0
+	for sc.Scan() {
+		line++
+		s := sc.Text()
+		if !strings.HasPrefix(s, "@") {
+			continue
+		}
+		entry := parseCiteName(s) // E.g., Doe2024a
+		entryToLine[entry] = line
+	}
+	if err := sc.Err(); err != nil {
+		log.Fatalf("scan file error: %v", err)
+	}
+
+	return func(entry string) int {
+		if line, ok := entryToLine[entry]; ok {
+			return line
+		}
+		log.Fatalf("could not find line number for cite name: %s", entry)
+		return -1
+	}
+}
+
+func parseCiteName(line string) string {
+	matches := re.FindStringSubmatch(line)
+	if len(matches) != 2 {
+		log.Fatalf("failed to extract cite name of: %s", line)
+	}
+	return matches[1]
+}
+
+func run(w io.Writer, bibEntries []bibEntry) {
+	fmt.Fprint(w, header())
+	makeBib(w, bibEntries)
+	fmt.Fprint(w, footer())
+}
+
+func main() {
+	path := flag.String("path", "", "Path to .bib file.")
+	flag.Parse()
+	if *path == "" {
+		log.Fatal("No path to .bib file provided.")
+	}
+	run(os.Stdout, parseBibFile(*path))
+	log.Println("Successfully created bibliography.")
+}