src/highlighter.go

   1 package main
   2
   3 import (
   4         "github.com/gdamore/tcell"
   5         "io/ioutil"
   6         "os/user"
   7         "path/filepath"
   8         "regexp"
   9         "strings"
  10 )
  11
  12 // FileTypeRules represents a complete set of syntax rules for a filetype
  13 type FileTypeRules struct {
  14         filetype string
  15         rules    []SyntaxRule
  16 }
  17
  18 // SyntaxRule represents a regex to highlight in a certain style
  19 type SyntaxRule struct {
  20         // What to highlight
  21         regex *regexp.Regexp
  22         // Any flags
  23         flags string
  24         // Whether this regex is a start=... end=... regex
  25         startend bool
  26         // How to highlight it
  27         style tcell.Style
  28 }
  29
  30 var syntaxFiles map[[2]*regexp.Regexp]FileTypeRules
  31
  32 // LoadSyntaxFiles loads the syntax files from the default directory ~/.micro
  33 func LoadSyntaxFiles() {
  34         usr, _ := user.Current()
  35         dir := usr.HomeDir
  36         LoadSyntaxFilesFromDir(dir + "/.micro/syntax")
  37 }
  38
  39 // JoinRule takes a syntax rule (which can be multiple regular expressions)
  40 // and joins it into one regular expression by ORing everything together
  41 func JoinRule(rule string) string {
  42         split := strings.Split(rule, `" "`)
  43         joined := strings.Join(split, ")|(")
  44         joined = "(" + joined + ")"
  45         return joined
  46 }
  47
  48 // LoadSyntaxFilesFromDir loads the syntax files from a specified directory
  49 // To load the syntax files, we must fill the `syntaxFiles` map
  50 // This involves finding the regex for syntax and if it exists, the regex
  51 // for the header. Then we must get the text for the file and the filetype.
  52 func LoadSyntaxFilesFromDir(dir string) {
  53         InitColorscheme()
  54
  55         syntaxFiles = make(map[[2]*regexp.Regexp]FileTypeRules)
  56         files, _ := ioutil.ReadDir(dir)
  57         for _, f := range files {
  58                 if filepath.Ext(f.Name()) == ".micro" {
  59                         text, err := ioutil.ReadFile(dir + "/" + f.Name())
  60                         filename := dir + "/" + f.Name()
  61
  62                         if err != nil {
  63                                 TermMessage("Error loading syntax files: " + err.Error())
  64                                 continue
  65                         }
  66                         lines := strings.Split(string(text), "\n")
  67
  68                         syntaxParser := regexp.MustCompile(`syntax "(.*?)"\s+"(.*)"+`)
  69                         headerParser := regexp.MustCompile(`header "(.*)"`)
  70
  71                         ruleParser := regexp.MustCompile(`color (.*?)\s+(?:\((.*?)\)\s+)?"(.*)"`)
  72                         ruleStartEndParser := regexp.MustCompile(`color (.*?)\s+(?:\((.*?)\)\s+)?start="(.*?)"\s+end="(.*?)"`)
  73
  74                         var syntaxRegex *regexp.Regexp
  75                         var headerRegex *regexp.Regexp
  76                         var filetype string
  77                         var rules []SyntaxRule
  78                         for lineNum, line := range lines {
  79                                 if strings.TrimSpace(line) == "" ||
  80                                         strings.TrimSpace(line)[0] == '#' {
  81                                         // Ignore this line
  82                                         continue
  83                                 }
  84
  85                                 if strings.HasPrefix(line, "syntax") {
  86                                         syntaxMatches := syntaxParser.FindSubmatch([]byte(line))
  87                                         if len(syntaxMatches) == 3 {
  88                                                 if syntaxRegex != nil {
  89                                                         regexes := [2]*regexp.Regexp{syntaxRegex, headerRegex}
  90                                                         syntaxFiles[regexes] = FileTypeRules{filetype, rules}
  91                                                 }
  92                                                 rules = rules[:0]
  93
  94                                                 filetype = string(syntaxMatches[1])
  95                                                 extensions := JoinRule(string(syntaxMatches[2]))
  96
  97                                                 syntaxRegex, err = regexp.Compile(extensions)
  98                                                 if err != nil {
  99                                                         TermError(filename, lineNum, err.Error())
 100                                                         continue
 101                                                 }
 102                                         } else {
 103                                                 TermError(filename, lineNum, "Syntax statement is not valid: "+line)
 104                                                 continue
 105                                         }
 106                                 } else if strings.HasPrefix(line, "header") {
 107                                         headerMatches := headerParser.FindSubmatch([]byte(line))
 108                                         if len(headerMatches) == 2 {
 109                                                 header := JoinRule(string(headerMatches[1]))
 110
 111                                                 headerRegex, err = regexp.Compile(header)
 112                                                 if err != nil {
 113                                                         TermError(filename, lineNum, "Regex error: "+err.Error())
 114                                                         continue
 115                                                 }
 116                                         } else {
 117                                                 TermError(filename, lineNum, "Header statement is not valid: "+line)
 118                                                 continue
 119                                         }
 120                                 } else {
 121                                         if ruleParser.MatchString(line) {
 122                                                 submatch := ruleParser.FindSubmatch([]byte(line))
 123                                                 var color string
 124                                                 var regexStr string
 125                                                 var flags string
 126                                                 if len(submatch) == 4 {
 127                                                         color = string(submatch[1])
 128                                                         flags = string(submatch[2])
 129                                                         regexStr = "(?" + flags + ")" + JoinRule(string(submatch[3]))
 130                                                 } else if len(submatch) == 3 {
 131                                                         color = string(submatch[1])
 132                                                         regexStr = JoinRule(string(submatch[2]))
 133                                                 } else {
 134                                                         TermError(filename, lineNum, "Invalid statement: "+line)
 135                                                 }
 136                                                 regex, err := regexp.Compile(regexStr)
 137                                                 if err != nil {
 138                                                         TermError(filename, lineNum, err.Error())
 139                                                         continue
 140                                                 }
 141
 142                                                 st := tcell.StyleDefault
 143                                                 if _, ok := colorscheme[color]; ok {
 144                                                         st = colorscheme[color]
 145                                                 } else {
 146                                                         st = StringToStyle(color)
 147                                                 }
 148                                                 rules = append(rules, SyntaxRule{regex, flags, false, st})
 149                                         } else if ruleStartEndParser.MatchString(line) {
 150                                                 submatch := ruleStartEndParser.FindSubmatch([]byte(line))
 151                                                 var color string
 152                                                 var start string
 153                                                 var end string
 154                                                 // Use m and s flags by default
 155                                                 flags := "ms"
 156                                                 if len(submatch) == 5 {
 157                                                         color = string(submatch[1])
 158                                                         flags = string(submatch[2])
 159                                                         start = string(submatch[3])
 160                                                         end = string(submatch[4])
 161                                                 } else if len(submatch) == 4 {
 162                                                         color = string(submatch[1])
 163                                                         start = string(submatch[2])
 164                                                         end = string(submatch[3])
 165                                                 } else {
 166                                                         TermError(filename, lineNum, "Invalid statement: "+line)
 167                                                 }
 168
 169                                                 regex, err := regexp.Compile("(?" + flags + ")" + "(" + start + ").*?(" + end + ")")
 170                                                 if err != nil {
 171                                                         TermError(filename, lineNum, err.Error())
 172                                                         continue
 173                                                 }
 174
 175                                                 st := tcell.StyleDefault
 176                                                 if _, ok := colorscheme[color]; ok {
 177                                                         st = colorscheme[color]
 178                                                 } else {
 179                                                         st = StringToStyle(color)
 180                                                 }
 181                                                 rules = append(rules, SyntaxRule{regex, flags, true, st})
 182                                         }
 183                                 }
 184                         }
 185                         if syntaxRegex != nil {
 186                                 regexes := [2]*regexp.Regexp{syntaxRegex, headerRegex}
 187                                 syntaxFiles[regexes] = FileTypeRules{filetype, rules}
 188                         }
 189                 }
 190         }
 191 }
 192
 193 // GetRules finds the syntax rules that should be used for the buffer
 194 // and returns them. It also returns the filetype of the file
 195 func GetRules(buf *Buffer) ([]SyntaxRule, string) {
 196         for r := range syntaxFiles {
 197                 if r[0] != nil && r[0].MatchString(buf.path) {
 198                         return syntaxFiles[r].rules, syntaxFiles[r].filetype
 199                 } else if r[1] != nil && r[1].MatchString(buf.lines[0]) {
 200                         return syntaxFiles[r].rules, syntaxFiles[r].filetype
 201                 }
 202         }
 203         return nil, "Unknown"
 204 }
 205
 206 // SyntaxMatches is an alias to a map from character numbers to styles,
 207 // so map[3] represents the style of the third character
 208 type SyntaxMatches map[int]tcell.Style
 209
 210 // Match takes a buffer and returns the syntax matches a map specifying how it should be syntax highlighted
 211 func Match(rules []SyntaxRule, buf *Buffer, v *View) SyntaxMatches {
 212         m := make(SyntaxMatches)
 213
 214         lineStart := v.updateLines[0]
 215         lineEnd := v.updateLines[1] + 1
 216         if lineStart < 0 {
 217                 // Don't need to update syntax highlighting
 218                 return m
 219         }
 220
 221         totalStart := v.topline - synLinesUp
 222         totalEnd := v.topline + v.height + synLinesDown
 223         if totalStart < 0 {
 224                 totalStart = 0
 225         }
 226         if totalEnd > len(buf.lines) {
 227                 totalEnd = len(buf.lines)
 228         }
 229
 230         if lineEnd > len(buf.lines) {
 231                 lineEnd = len(buf.lines)
 232         }
 233
 234         lines := buf.lines[lineStart:lineEnd]
 235         str := strings.Join(buf.lines[totalStart:totalEnd], "\n")
 236         startNum := v.cursor.loc + v.cursor.Distance(0, totalStart)
 237         toplineNum := v.cursor.loc + v.cursor.Distance(0, v.topline)
 238         for _, rule := range rules {
 239                 if rule.startend && rule.regex.MatchString(str) {
 240                         indicies := rule.regex.FindAllStringIndex(str, -1)
 241                         for _, value := range indicies {
 242                                 value[0] += startNum
 243                                 value[1] += startNum
 244                                 for i := value[0]; i < value[1]; i++ {
 245                                         if i >= toplineNum {
 246                                                 m[i] = rule.style
 247                                         }
 248                                 }
 249                         }
 250                 } else {
 251                         for _, line := range lines {
 252                                 if rule.regex.MatchString(line) {
 253                                         indicies := rule.regex.FindAllStringIndex(str, -1)
 254                                         for _, value := range indicies {
 255                                                 value[0] += toplineNum
 256                                                 value[1] += toplineNum
 257                                                 for i := value[0]; i < value[1]; i++ {
 258                                                         m[i] = rule.style
 259                                                 }
 260                                         }
 261                                 }
 262                         }
 263                 }
 264         }
 265
 266         return m
 267 }