163 lines
4 KiB
Go
163 lines
4 KiB
Go
/* SHS: Syntactically Homogeneous Shell
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* Copyright (C) 2019 Aidan Hahn
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package main
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import (
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"os"
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"fmt"
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"strconv"
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"github.com/peterh/liner"
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"gitlab.com/whom/shs/ast"
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"gitlab.com/whom/shs/log"
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"gitlab.com/whom/shs/config"
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)
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const (
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def_prompt string = "λ "
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)
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// useful for when input contains escape sequences
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// not checking delims cause thats up to the user who defines their prompts
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func parseString(in string) string {
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in = "\"" + in + "\""
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out, err := strconv.Unquote(in)
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if err != nil {
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log.Log(log.ERR,
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"Couldnt parse (pre?)prompt",
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"init")
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return ""
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}
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return out
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}
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func setLogLvl(vars ast.VarTable) {
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var loglvl string
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loglvl_t := ast.GetVar("SH_LOGGING", vars)
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if loglvl_t != nil {
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loglvl = loglvl_t.Value()
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}
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if loglvl != "" {
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llvl, err := strconv.ParseInt(loglvl, 10, 8)
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if err != nil {
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log.Log(log.ERR,
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"couldnt parse log level: " + err.Error(),
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"init")
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} else {
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log.SetLogLvl(llvl)
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}
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}
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}
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func main() {
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var prompt string
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var debug string
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var hist string
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no_hist := false
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ast.SyncTablesWithOSEnviron = true
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ast.ExecWhenFuncUndef = true
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vars, funcs := config.InitFromConfig(".shsrc")
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debug_t := ast.GetVar("SH_DEBUG_MODE", vars)
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if debug_t != nil {
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debug = debug_t.Value()
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}
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hist_t := ast.GetVar("SH_HIST_FILE", vars)
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if hist_t != nil {
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hist = hist_t.Value()
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} else {
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no_hist = true
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}
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dyn_prompt := ast.GetFunction("_SH_PROMPT", funcs)
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if dyn_prompt == nil || dyn_prompt.Args != 0 {
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dyn_prompt = nil
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}
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prompt_t := ast.GetVar("SHS_STATIC_PROMPT", vars)
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if prompt_t != nil {
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prompt = parseString(prompt_t.Value())
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} else {
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prompt = def_prompt
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}
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line := liner.NewLiner()
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defer line.Close()
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line.SetCtrlCAborts(true)
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var histFile *os.File
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var err error
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if !no_hist {
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histFile, err = os.Open(hist)
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if err == nil {
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line.ReadHistory(histFile)
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} else {
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log.Log(log.ERR,
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"couldnt read history: " + err.Error(),
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"repl")
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}
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defer histFile.Close()
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}
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for {
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setLogLvl(vars)
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var prePrompt string
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if dyn_prompt != nil {
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p_tok := dyn_prompt.CallFunction(nil, vars, funcs)
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if p_tok != nil && p_tok.Tag == ast.STRING {
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prePrompt = parseString(p_tok.Value())
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}
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}
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fmt.Printf(prePrompt)
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text, err := line.Prompt(prompt)
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if err != nil && err != liner.ErrPromptAborted{
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log.Log(log.ERR, "couldnt read user input: " + err.Error(), "repl")
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}
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if !no_hist {
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line.WriteHistory(histFile)
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}
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userInput := ast.Lex(text)
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if userInput == nil {
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// errors handled in Lex
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// TODO: return an error instead
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continue
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}
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if debug != "" {
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ast.PrintSExprsIndividually(userInput)
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}
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result := userInput.Eval(funcs, vars, false)
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if result != nil {
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for i := result; i != nil; i = i.Next {
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fmt.Printf(i.String() + " ")
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}
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}
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fmt.Printf("\n")
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}
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}
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