From e85ae907a0cb9046e640c4f06b5b4f7142c39033 Mon Sep 17 00:00:00 2001
From: Zachary Yedidia <zyedidia@gmail.com>
Date: Tue, 21 Mar 2017 14:35:58 -0400
Subject: [PATCH] Add syntax converter from old file format to new

---
 runtime/syntax/syntax_converter.go | 168 +++++++++++++++++++++++++++++
 1 file changed, 168 insertions(+)
 create mode 100644 runtime/syntax/syntax_converter.go

diff --git a/runtime/syntax/syntax_converter.go b/runtime/syntax/syntax_converter.go
new file mode 100644
index 00000000..eb1f4262
--- /dev/null
+++ b/runtime/syntax/syntax_converter.go
@@ -0,0 +1,168 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"regexp"
+	"strings"
+)
+
+type SingleRule struct {
+	color string
+	regex string
+}
+
+type MultiRule struct {
+	color string
+	start string
+	end   string
+}
+
+// JoinRule takes a syntax rule (which can be multiple regular expressions)
+// and joins it into one regular expression by ORing everything together
+func JoinRule(rule string) string {
+	split := strings.Split(rule, `" "`)
+	joined := strings.Join(split, "|")
+	joined = joined
+	return joined
+}
+
+func parseFile(text, filename string) (filetype, syntax, header string, rules []interface{}) {
+	lines := strings.Split(text, "\n")
+
+	// Regex for parsing syntax statements
+	syntaxParser := regexp.MustCompile(`syntax "(.*?)"\s+"(.*)"+`)
+	// Regex for parsing header statements
+	headerParser := regexp.MustCompile(`header "(.*)"`)
+
+	// Regex for parsing standard syntax rules
+	ruleParser := regexp.MustCompile(`color (.*?)\s+(?:\((.+?)?\)\s+)?"(.*)"`)
+	// Regex for parsing syntax rules with start="..." end="..."
+	ruleStartEndParser := regexp.MustCompile(`color (.*?)\s+(?:\((.+?)?\)\s+)?start="(.*)"\s+end="(.*)"`)
+
+	for lineNum, line := range lines {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		if strings.HasPrefix(line, "#") {
+			continue
+		}
+		if strings.HasPrefix(line, "syntax") {
+			syntaxMatches := syntaxParser.FindSubmatch([]byte(line))
+			if len(syntaxMatches) == 3 {
+				filetype = string(syntaxMatches[1])
+				syntax = JoinRule(string(syntaxMatches[2]))
+			} else {
+				fmt.Println(filename, lineNum, "Syntax statement is not valid: "+line)
+				continue
+			}
+		}
+		if strings.HasPrefix(line, "header") {
+			// Header statement
+			headerMatches := headerParser.FindSubmatch([]byte(line))
+			if len(headerMatches) == 2 {
+				header = JoinRule(string(headerMatches[1]))
+			} else {
+				fmt.Println(filename, lineNum, "Header statement is not valid: "+line)
+				continue
+			}
+		}
+
+		// Syntax rule, but it could be standard or start-end
+		if ruleParser.MatchString(line) {
+			// Standard syntax rule
+			// Parse the line
+			submatch := ruleParser.FindSubmatch([]byte(line))
+			var color string
+			var regexStr string
+			var flags string
+			if len(submatch) == 4 {
+				// If len is 4 then the user specified some additional flags to use
+				color = string(submatch[1])
+				flags = string(submatch[2])
+				if flags != "" {
+					regexStr = "(?" + flags + ")" + JoinRule(string(submatch[3]))
+				} else {
+					regexStr = JoinRule(string(submatch[3]))
+				}
+			} else if len(submatch) == 3 {
+				// If len is 3, no additional flags were given
+				color = string(submatch[1])
+				regexStr = JoinRule(string(submatch[2]))
+			} else {
+				// If len is not 3 or 4 there is a problem
+				fmt.Println(filename, lineNum, "Invalid statement: "+line)
+				continue
+			}
+
+			rules = append(rules, SingleRule{color, regexStr})
+		} else if ruleStartEndParser.MatchString(line) {
+			// Start-end syntax rule
+			submatch := ruleStartEndParser.FindSubmatch([]byte(line))
+			var color string
+			var start string
+			var end string
+			// Use m and s flags by default
+			flags := "ms"
+			if len(submatch) == 5 {
+				// If len is 5 the user provided some additional flags
+				color = string(submatch[1])
+				flags += string(submatch[2])
+				start = string(submatch[3])
+				end = string(submatch[4])
+			} else if len(submatch) == 4 {
+				// If len is 4 the user did not provide additional flags
+				color = string(submatch[1])
+				start = string(submatch[2])
+				end = string(submatch[3])
+			} else {
+				// If len is not 4 or 5 there is a problem
+				fmt.Println(filename, lineNum, "Invalid statement: "+line)
+				continue
+			}
+
+			// rules[color] = "(?" + flags + ")" + "(" + start + ").*?(" + end + ")"
+			rules = append(rules, MultiRule{color, start, end})
+		}
+	}
+
+	return
+}
+
+func generateFile(filetype, syntax, header string, rules []interface{}) string {
+	output := ""
+
+	output += fmt.Sprintf("filetype: %s\n\n", filetype)
+	output += fmt.Sprintf("detect: \n\tfilename: \"%s\"\n", strings.Replace(syntax, "\\", "\\\\", -1))
+
+	if header != "" {
+		output += fmt.Sprintf("\theader: \"%s\"\n", strings.Replace(header, "\\", "\\\\", -1))
+	}
+
+	output += "\nrules:\n"
+
+	for _, r := range rules {
+		if rule, ok := r.(SingleRule); ok {
+			output += fmt.Sprintf("\t- %s: \"%s\"\n", rule.color, strings.Replace(strings.Replace(rule.regex, "\\", "\\\\", -1), "\"", "\\\"", -1))
+		} else if rule, ok := r.(MultiRule); ok {
+			output += fmt.Sprintf("\t- %s:\n", rule.color)
+			output += fmt.Sprintf("\t\tstart: \"%s\"\n", rule.start)
+			output += fmt.Sprintf("\t\tend: \"%s\"\n", rule.end)
+			output += fmt.Sprintf("\t\trules: []\n\n")
+		}
+	}
+
+	return output
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Println("no args")
+		return
+	}
+
+	data, _ := ioutil.ReadFile(os.Args[1])
+	fmt.Print(generateFile(parseFile(string(data), os.Args[1])))
+}