92 lines
1.6 KiB
Go
92 lines
1.6 KiB
Go
package main
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import (
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"fmt"
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logpkg "log"
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"os"
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"gitea.xintech.co/zhouzhihong/lexmachine/frontend"
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"github.com/timtadh/getopt"
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)
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var log *logpkg.Logger
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func init() {
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log = logpkg.New(os.Stderr, "", 0)
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}
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var usageMessage = "lexc -p <pattern> [-p <pattern>]*"
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var extendedMessage = `
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lexc compiles regular expressions to a program suitable for lexing
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Options
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-h, --help print this message
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-p, --pattern=<pattern> a regex pattern
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Specs
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<pattern>
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a regex pattern
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`
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func usage(code int) {
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fmt.Fprintln(os.Stderr, usageMessage)
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if code == 0 {
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fmt.Fprintln(os.Stderr, extendedMessage)
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code = 1
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} else {
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fmt.Fprintln(os.Stderr, "Try -h or --help for help")
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}
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os.Exit(code)
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}
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func main() {
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short := "hp:"
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long := []string{
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"help",
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"pattern=",
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}
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_, optargs, err := getopt.GetOpt(os.Args[1:], short, long)
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if err != nil {
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log.Print(err)
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usage(1)
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}
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patterns := make([]string, 0, 10)
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for _, oa := range optargs {
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switch oa.Opt() {
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case "-h", "--help":
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usage(0)
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case "-p", "--pattern":
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patterns = append(patterns, oa.Arg())
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}
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}
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if len(patterns) <= 0 {
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log.Print("Must supply some regulars expressions!")
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usage(1)
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}
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asts := make([]frontend.AST, 0, len(patterns))
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for _, p := range patterns {
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ast, err := frontend.Parse([]byte(p))
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if err != nil {
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log.Fatal(err)
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}
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asts = append(asts, ast)
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}
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lexast := asts[len(asts)-1]
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for i := len(asts) - 2; i >= 0; i-- {
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lexast = frontend.NewAltMatch(asts[i], lexast)
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}
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program, err := frontend.Generate(lexast)
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if err != nil {
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log.Fatal(err)
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}
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fmt.Println(program.Serialize())
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}
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