avoid disaster regarding setting of env variables from number tokens

ast/var_table.go

@@ -19,15 +19,25 @@ package ast
 
 import (
     "os"
+    "fmt"
+    "math"
+    "strconv"
     "strings"
     "git.callpipe.com/aidan/shs/log"
 )
 
+// Trigger this if you are using this for a shell
+var SyncTablesWithOSEnviron = false
+
 type VarTable *map[string]*Token
 
 func GetVar(arg string, vt VarTable) *Token {
     val, ok := (*vt)[arg]
     if !ok {
+        if !SyncTablesWithOSEnviron {
+            return nil
+        }
+
         e := os.Getenv(arg)
         if e != "" {
             t := &Token{Inner: e}
@@ -45,11 +55,20 @@ func GetVar(arg string, vt VarTable) *Token {
     return val
 }
 
-// TODO: Document me :)
+// TODO: this could be much more optimal
 func SetVar(variable string, value *Token, vt VarTable) {
     (*vt)[variable] = value
-    if value.Tag == NUMBER || value.Tag == STRING {
-        os.Setenv(variable, value.Inner.(string))
+    if SyncTablesWithOSEnviron && 
+       (value.Tag == NUMBER || value.Tag == STRING) {
+        token := value.Inner.(string)
+        if value.Tag == NUMBER {
+            // make sure its an int
+            a, err := strconv.ParseFloat(token, 64)
+            if err == nil && math.Mod(a, 1.0) == 0 {
+                token = fmt.Sprintf("%d", int(a))
+            }
+        }
+        os.Setenv(variable, token)
     }
 }
 

cmd/repl.go

@@ -57,6 +57,7 @@ func main() {
     funcs = stdlib.GenFuncTable()
     vars = &map[string]*ast.Token{}
     ast.InitVarTable(vars)
+    ast.SyncTablesWithOSEnviron = true
 
     useHist := false
     var histFile *os.File