1 files changed, 167 insertions, 0 deletions
diff --git a/ref.go b/ref.go
new file mode 100644
index 0000000..ba30c79
--- /dev/null
+++ b/ref.go
@@ -0,0 +1,167 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+	"sort"
+	"io"
+)
+
+const (
+	bufsize = 512
+	prefix  = `.\"s `
+	end = `.\"e`
+	section = `.\"§`
+	tableHead = ".TS\nexpand;\nl1w(1.5i) l1w(4.5i)."
+	tableFoot = ".TE"
+	mac = ".ref"
+	delim = "()"
+	extraPrefix = `\fC`
+	extraSuffix = `\fP`
+)
+
+type Reference struct {
+	name  string
+	contents string
+	index int
+}
+
+func getRefTxt(lines []string) string {
+	var txt string
+	for _, line := range lines {
+		if strings.HasPrefix(line, end) {
+			break
+		}
+		txt += line + "\n"
+	}
+	return string(txt)
+}
+
+func findIndex(refs []Reference, name string) int {
+	for _, ref := range refs {
+		if ref.name == name {
+			return ref.index
+		}
+	}
+	return -1
+}
+
+func checkLetter(ch rune) bool {
+	if ch >= 'A' && ch <= 'Z' ||
+		ch >= 'a' && ch <= 'z' {
+		return true
+	}
+	return false
+}
+
+func checkAllCaps(word string) bool {
+	for _, ch := range word {
+		if !checkLetter(ch) {
+			continue
+		}
+		if ch < 'A' || ch > 'Z' {
+			return false
+		}
+	}
+	return true
+}
+// Typographic niceties.
+func extraFmt(ref string) string {
+	words := strings.Split(ref, " ")
+	if checkAllCaps(words[0]) {
+		words[0] = extraPrefix + words[0] + extraSuffix
+	}
+	words[1] = extraPrefix + words[1] + extraSuffix
+
+	return words[0] + " " + words[1]
+}
+
+func main() {
+	in := os.Stdin
+	if len(os.Args) > 1 {
+		var err error
+		in, err = os.Open(os.Args[1])
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	bytes, err := io.ReadAll(in)
+	if err != nil {
+		log.Fatal(err)
+	}
+	contents := string(bytes)
+
+	/* Iterate through the contents of the file twice:
+	Once to find and index all references.
+	Again to refer to each reference. */
+	var refs []Reference
+	div := -1
+	lines := strings.Split(contents, "\n")
+	for i, line := range lines {
+		if line == section {
+			div = i
+		}
+	}
+	// If no split, quietly return contents.
+	if div == -1 {
+		fmt.Print(contents)
+		return
+	}
+
+	for i, line := range lines[div:] {
+		if strings.HasPrefix(line, prefix) {
+			var ref Reference
+			ref.name = line[len(prefix):]
+			// i is relative to the lines after div.
+			ref.contents = getRefTxt(lines[div+i+1:])
+			refs = append(refs, ref)
+		}
+	}
+
+	/* Sort references alphabetically. */
+	sort.Slice(refs, func(i, j int) bool {
+		return strings.Compare(refs[i].name, refs[j].name) < 0
+	})
+
+	for i := range refs {
+		refs[i].index = i
+	}
+
+	// Second pass.
+	for _, line := range lines[:div] {
+		if strings.HasPrefix(line, mac) {
+			var name string
+			var start, end int
+			for i := range line {
+				if line[i] == delim[0] {
+					start = i+1
+				}
+				if line[i] == delim[1] {
+					end = i
+					break
+				}
+			}
+			name = line[start:end]
+			index := findIndex(refs, name)
+			fmt.Printf(".post.url #%d \"%s\"\n\n", index,
+				extraFmt(line[start-1:]))
+		} else {
+			fmt.Println(line)
+		}
+	}
+
+	// Format References into AMS Style bibiography.
+	/* As it turns out, in order to be referenced individually,
+	each reference needs its own table. */
+	for _, ref := range refs {
+		fmt.Printf(".post.name %d\n", ref.index)
+		fmt.Println(tableHead)
+		fmt.Printf("T{\n%c%s%c\nT}", delim[0], extraFmt(ref.name),
+			delim[1])
+		fmt.Printf("\tT{\n%s\nT}\n", ref.contents)
+		fmt.Println(tableFoot)
+	}
+}