We know have an std lib implementation

lib/std.msh

@@ -2,20 +2,17 @@
 
 # each (list quote --)
 def each 
-    over len # Get total length
-    0 # index
+    over len @each-len # Get total length
+    0 @each-idx # index
     (
-        [(over over <=) (break)] if
-        # list quote len index index  
-        dup 5 pick nth 
-        # list quote len index item
-        4 pick x
-        drop
-        1 + # inc index
+        [(each-idx! each-len! >=) (break)] if
+        over each-idx! nth # Get current item
+        over x # Copy over quote, execute
+        each-idx! 1 + @each-idx # inc index
     ) loop
 
     # Drop list and quote, total length, index
-    drop drop drop drop
+    drop drop
 end
 
 # map (list quote -- list)
@@ -37,6 +34,12 @@ def map
     drop drop map-accum!
 end
 
+# .. (-- str)
+def .. stdin end
+
+# tt = Tab separated Table (-- list[list[str]])
+def tt stdin lines ("	" split) map end
+
 # map (list quote -- list)
 # [seq 1 1000]o; ("Line #" over str + wl) each
 # [1 2 3] (2 +) map .s

mshell-go/Evaluator.go

@@ -469,7 +469,7 @@ func (state *EvalState) Evaluate(objects []MShellParseItem, stack *MShellStack,
                             }
                         }
                     default:
-                        return FailWithMessage(fmt.Sprintf("%d:%d: Cannot join a %s.\n", t.Line, t.Column, list.TypeName()))
+                        return FailWithMessage(fmt.Sprintf("%d:%d: Cannot join a %s (%s).\n", t.Line, t.Column, list.TypeName(), list.DebugString()))
                     }
 
                     stack.Push(&MShellString { strings.Join(listItems, delimiterStr) })

mshell-go/Main.go

@@ -105,16 +105,6 @@ func main() {
         return
     }
 
-    p := MShellParser{ lexer: l }
-    p.NextToken()
-    file, err := p.ParseFile()
-    if err != nil {
-        fmt.Fprintf(os.Stderr, "Error parsing file %s: %s\n", input, err)
-        os.Exit(1)
-        return
-    }
-
-    // tokens := l.Tokenize()
     state := EvalState {
         PositionalArgs: positionalArgs,
         LoopDepth: 0,
@@ -128,7 +118,48 @@ func main() {
         StandardOutput: os.Stdout,
     }
 
-    result := state.Evaluate(file.Items, &stack, context, file.Definitions)
+    var allDefinitions []MShellDefinition
+
+    // Check for environment variable MSHSTDLIB and load that file. Read as UTF-8
+    stdlibPath, stdlibSet := os.LookupEnv("MSHSTDLIB")
+    if stdlibSet {
+        stdlibBytes, err := os.ReadFile(stdlibPath)
+        if err != nil {
+            fmt.Fprintf(os.Stderr, "Error reading file %s: %s\n", stdlibPath, err)
+            os.Exit(1)
+            return
+        }
+        stdlibLexer := NewLexer(string(stdlibBytes))
+        stdlibParser := MShellParser{ lexer: stdlibLexer }
+        stdlibParser.NextToken()
+        stdlibFile, err := stdlibParser.ParseFile()
+        if err != nil {
+            fmt.Fprintf(os.Stderr, "Error parsing file %s: %s\n", stdlibPath, err)
+            os.Exit(1)
+            return
+        }
+
+        allDefinitions = append(allDefinitions, stdlibFile.Definitions...)
+        result := state.Evaluate(stdlibFile.Items, &stack, context, allDefinitions)
+
+        if !result.Success {
+            fmt.Fprintf(os.Stderr, "Error evaluating MSHSTDLIB file %s.\n", stdlibPath)
+            os.Exit(1)
+            return
+        }
+    }
+
+    p := MShellParser{ lexer: l }
+    p.NextToken()
+    file, err := p.ParseFile()
+    if err != nil {
+        fmt.Fprintf(os.Stderr, "Error parsing file %s: %s\n", input, err)
+        os.Exit(1)
+        return
+    }
+
+    allDefinitions = append(allDefinitions, file.Definitions...)
+    result := state.Evaluate(file.Items, &stack, context, allDefinitions)
 
     if !result.Success {
         os.Exit(1)

mshell/tests/std_lib.msh

@@ -0,0 +1,3 @@
+[1 2 3] (2 + str) map ", " join wl
+
+[1 2 3] ([printf "%d\n"] append ;) each

mshell/tests/std_lib.msh.stdout

@@ -0,0 +1,4 @@
+3, 4, 5
+1
+2
+3

mshell/tests/test_file_go.sh

@@ -2,6 +2,9 @@
 TMP_FILE="$(mktemp)"
 TMP_ERR="$(mktemp)"
 
+MSHSTDLIB="$(realpath ../../lib/std.msh)"
+export MSHSTDLIB
+
 if printf %s "$1" | grep -q 'positional'; then
     mshell-go "$1" Hello World > "$TMP_FILE" 2>"$TMP_ERR"
 elif test "$(basename "$1")" = "args.msh"; then