comments support, script loading support

Readme.md

@@ -49,6 +49,10 @@ See `stdlib/control_flow.go`. We have if and while forms:
 
 We also have functioning implementations of map and reduce in the stdlib (incomplete)
 
+## Comments
+The standard delimiter for comments is ;
+any characters after a semicolon will be ignored until end of line
+
 ## How to build
 ### Compiling/Installation
 - For now simply run `go install cmd/...` for each utility you wish to use. If you have GOPATH and GOBIN set it should be usable from PATH
@@ -69,9 +73,14 @@ We also have functioning implementations of map and reduce in the stdlib (incomp
 * one can write arbitrary shs script into `.shsrc` including function and variable declarations
 * of note are the following variables
     - `SH_LOGGING` Sets the log level (from 0 to 3)
-    - `SHS_SH_PROMPT` Sets the prompt
+    - `SHS_STATIC_PROMPT` Sets the prompt
     - `SH_HIST_FILE` Sets the history file
-    - `SH_DEBUG_MODE` Adds additional debug output for the lexer
+    - `SH_DEBUG_MODE` Adds additional debug output for the lexer (high clutter)
+* additionally, the repl will evaluate any function you define as `_SH_PROMPT` before the shell prompt
+    - if defined, the function will be evaluated before printing the prompt
+    - the function will be given 0 arguments
+    - if the function does not return a string, its output will be discarded
+    - afterwards, the repl will print the values in `SHS_STATIC_PROMPT`
 Here is an example of a shs configuration file:
 ```lisp
 (export GOPATH (concat HOME     "/go"))
@@ -80,6 +89,8 @@ Here is an example of a shs configuration file:
 (export GIT_TERMINAL_PROMPT 1)
 (export SH_HIST_FILE (concat HOME "/.shs_hist"))
 (export SH_LOGGING 0)
+(export SHS_STATIC_PROMPT ">")
+(func _SH_PROMPT () (concat (?) ($ basename ($ pwd)) "\n"))
 ```
 
 ## Contributing

ast/eval.go

@@ -61,6 +61,8 @@ func (in *Token) Eval(funcs FuncTable, vars VarTable, cnvtUndefVars bool) *Token
                     "eval")
                 return nil
             }
+        } else {
+            res.Next = in.Next
         }
 
     case LIST:

ast/lex.go

@@ -121,6 +121,17 @@ func lex(input string) *Token {
         return -2
     }
 
+    // returns the end of the string OR the end of the line
+    matchLineEnd := func(start int) int {
+        for i := start; i < len(input); i++ {
+            if input[i] == '\n' {
+                return i
+            }
+        }
+
+        return len(input)
+    }
+
     needs_alloc := false
     start_pos := 0
     for i := 0; i < len(input); i++ {
@@ -137,13 +148,18 @@ func lex(input string) *Token {
             is_str = true
             needs_alloc = true
 
-        case ' ':
+        case ' ', '\n', '\t', '\v', '\f', '\r':
             if i == start_pos {
                 start_pos += 1
                 continue
             }
 
             needs_alloc = true
+
+        // comment case
+        case ';':
+            start_pos = i + 1
+            i = matchLineEnd(start_pos)
         }
 
         if needs_alloc {

cmd/shs_repl.go

@@ -18,9 +18,10 @@
 package main
 
 import (
+    "os"
     "fmt"
     "strconv"
-    "github.com/chzyer/readline"
+    "github.com/peterh/liner"
     "gitlab.com/whom/shs/ast"
     "gitlab.com/whom/shs/log"
     "gitlab.com/whom/shs/config"
@@ -54,6 +55,7 @@ func main() {
     var prompt string
     var debug string
     var hist string
+    no_hist := false
 
     ast.SyncTablesWithOSEnviron = true
     ast.ExecWhenFuncUndef = true
@@ -67,34 +69,61 @@ func main() {
     hist_t := ast.GetVar("SH_HIST_FILE", vars)
     if hist_t != nil {
         hist = hist_t.Value()
+    } else {
+        no_hist = true
     }
 
-    prompt_t := ast.GetVar("SHS_SH_PROMPT", vars)
+    dyn_prompt := ast.GetFunction("_SH_PROMPT", funcs)
+    if dyn_prompt == nil || dyn_prompt.Args != 0 {
+        dyn_prompt = nil
+    }
+
+    prompt_t := ast.GetVar("SHS_STATIC_PROMPT", vars)
     if prompt_t != nil {
         prompt = prompt_t.Value()
     } else {
         prompt = def_prompt
     }
 
-    rl, err := readline.NewEx(&readline.Config{
-        Prompt: prompt,
-        HistoryFile: hist,
-        InterruptPrompt: "^C",
-    })
+    line := liner.NewLiner()
+    defer line.Close()
 
-    defer rl.Close()
-    if err != nil {
-        log.Log(log.ERR, "Couldnt initialize readline: " + err.Error(), "repl")
-        return
+    line.SetCtrlCAborts(true)
+
+    var histFile *os.File
+    var err error
+    if !no_hist {
+        histFile, err = os.Open(hist)
+        if err == nil {
+            line.ReadHistory(histFile)
+        } else {
+            log.Log(log.ERR,
+                "couldnt read history: " + err.Error(),
+                "repl")
+        }
+        defer histFile.Close()
     }
 
     for {
         setLogLvl(vars)
-        text, err := rl.Readline()
-        if err != nil {
+        var prePrompt string
+        if dyn_prompt != nil {
+            p_tok := dyn_prompt.CallFunction(nil, vars, funcs)
+            if p_tok != nil && p_tok.Tag == ast.STRING {
+                prePrompt = p_tok.Value()
+            }
+        }
+
+        fmt.Printf(prePrompt)
+        text, err := line.Prompt(prompt)
+        if err != nil && err != liner.ErrPromptAborted{
             log.Log(log.ERR, "couldnt read user input: " + err.Error(), "repl")
         }
 
+        if !no_hist {
+            line.WriteHistory(histFile)
+        }
+
         userInput := ast.Lex(text)
         if userInput == nil {
             // errors handled in Lex

config/config.go

@@ -18,11 +18,9 @@
 package config
 
 import (
-    "os"
-    "io"
-    "bufio"
     "gitlab.com/whom/shs/log"
     "gitlab.com/whom/shs/ast"
+    "gitlab.com/whom/shs/util"
     "gitlab.com/whom/shs/stdlib"
 )
 
@@ -35,32 +33,10 @@ func InitFromConfig(configFile string) (ast.VarTable, ast.FuncTable) {
     p := ast.GetVar("HOME", vars)
     configFile = p.Value() + "/" + configFile
 
-    cfile, err := os.Open(configFile)
-    if err != nil {
-        log.Log(log.DEBUG,
-            "unable to open config file: " + err.Error(),
-            "config")
-        return vars, funcs
-    }
-
-    r := bufio.NewReader(cfile)
-    text, err := r.ReadString('\n')
-    for err != io.EOF {
-        if err != nil {
-            log.Log(log.ERR,
-                "unable to read from config file: " + err.Error(),
-                "config")
-            break
-        }
-
-        // Eval lines in config
-        ast.Lex(text).Eval(funcs, vars, false)
-        text, err = r.ReadString('\n')
-    }
+    util.LoadScript(configFile, vars, funcs)
 
     log.Log(log.DEBUG,
         "config file fully evaluated",
         "config")
-    cfile.Close()
     return vars, funcs
 }

go.mod

@@ -2,4 +2,7 @@ module gitlab.com/whom/shs
 
 go 1.14
 
-require github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e // indirect
+require (
+	github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e // indirect
+	github.com/peterh/liner v1.2.0 // indirect
+)

go.sum

@@ -1,2 +1,6 @@
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e h1:fY5BOSpyZCqRo5OhCuC+XN+r/bBCmeuuJtjz+bCNIf8=
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
+github.com/mattn/go-runewidth v0.0.3 h1:a+kO+98RDGEfo6asOGMmpodZq4FNtnGP54yps8BzLR4=
+github.com/mattn/go-runewidth v0.0.3/go.mod h1:LwmH8dsx7+W8Uxz3IHJYH5QSwggIsqBzpuz5H//U1FU=
+github.com/peterh/liner v1.2.0 h1:w/UPXyl5GfahFxcTOz2j9wCIHNI+pUPr2laqpojKNCg=
+github.com/peterh/liner v1.2.0/go.mod h1:CRroGNssyjTd/qIG2FyxByd2S8JEAZXBl4qUrZf8GS0=

stdlib/call.go

@@ -254,8 +254,14 @@ func read_cmd(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
         }
     }
 
+    output := out.String()
+    olen := len(output)
+    if olen > 0 && output[olen - 1] == '\n' {
+        output = output[:olen - 1]
+    }
+
     ret := &ast.Token{Tag: ast.STRING}
-    ret.Set(out.String())
+    ret.Set(output)
     return ret
 
 }

stdlib/funcs.go

@@ -60,7 +60,9 @@ func decl_func(input *ast.Token, vars ast.VarTable, funcs ast.FuncTable) *ast.To
 
     ASTSYNCSTATE := ast.SyncTablesWithOSEnviron
     inner := func(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
-        temp := in.Eval(ft, vt, false)
+        var temp *ast.Token
+        if numArgs != 0 || in != nil {
+            temp = in.Eval(ft, vt, false)
             if temp == nil {
                 log.Log(log.ERR,
                     "error parsing arguments",
@@ -83,7 +85,9 @@ func decl_func(input *ast.Token, vars ast.VarTable, funcs ast.FuncTable) *ast.To
                 key_iter = key_iter.Next
                 val_iter = val_iter.Next
             }
+        }
 
+        // maybe we actually should put the inner scope var into the env
         ast.SyncTablesWithOSEnviron = ASTSYNCSTATE
         ret := form.Eval(ft, vt, false)
         ast.SyncTablesWithOSEnviron = false

stdlib/stdlib.go

@@ -22,6 +22,7 @@ import (
     "fmt"
     "gitlab.com/whom/shs/log"
     "gitlab.com/whom/shs/ast"
+    "gitlab.com/whom/shs/util"
 )
 
 func GenFuncTable() ast.FuncTable {
@@ -69,6 +70,13 @@ func GenFuncTable() ast.FuncTable {
             Args:          1,
         },
 
+        "load": &ast.Function{
+            Function:    load,
+            Name:      "load",
+            TimesCalled:    0,
+            Args:           1,
+        },
+
         "...": &ast.Function{
             Function: expand,
             Name:      "...",
@@ -337,3 +345,18 @@ func input(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
     ret.Set(output)
     return ret
 }
+
+func load(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
+    in = in.Eval(ft, vt, true)
+    if in.Tag != ast.STRING {
+        log.Log(log.ERR,
+            "argument to load must be a string",
+            "load")
+        return nil
+    }
+
+    bp := in.Value()
+    bp = AbsPath(bp)
+    util.LoadScript(bp, vt, ft)
+    return nil
+}

util/scripts.go

@@ -19,7 +19,7 @@ package util
 
 import (
     "os"
-    "os/ioutil"
+    "io/ioutil"
     "gitlab.com/whom/shs/log"
     "gitlab.com/whom/shs/ast"
 )
@@ -33,16 +33,18 @@ func LoadScript(path string, vt ast.VarTable, ft ast.FuncTable) {
         return
     }
 
-    var body string
-    body, err := ioutil.ReadFile(path)
+    var body []byte
+    body, err = ioutil.ReadFile(path)
     scriptFile.Close()
-    if err !- nil {
+    if err != nil {
         log.Log(log.ERR,
             "unable to read script: " + err.Error(),
             "util")
         return
     }
 
-    set := ast.Lex(body)
-    set.Eval(ft, vt, false)
+    set := ast.Lex(string(body))
+    for iter := set; iter != nil; iter = iter.Next {
+        iter.Eval(ft, vt, false)
+    }
 }