From 99c71cae9fe53e9db7ae6b90b5be576d9aad7f28 Mon Sep 17 00:00:00 2001
From: Steve Kemp <steve@steve.org.uk>
Date: Tue, 22 Nov 2022 06:30:27 +0200
Subject: [PATCH] Moved (env) from the core to the builtin package.

This will close #99, once complete.
---
 builtins/builtins.go      | 29 +++++++++++++++++++++++++++++
 builtins/builtins_test.go | 38 ++++++++++++++++++++++++++++++++++++++
 builtins/help.txt         |  4 ++++
 eval/specials.go          | 27 ---------------------------
 4 files changed, 71 insertions(+), 27 deletions(-)

diff --git a/builtins/builtins.go b/builtins/builtins.go
index 890040f..1fa137e 100644
--- a/builtins/builtins.go
+++ b/builtins/builtins.go
@@ -111,6 +111,7 @@ func PopulateEnvironment(env *env.Environment) {
 	env.Set("date", &primitive.Procedure{F: dateFn, Help: helpMap["date"]})
 	env.Set("directory:entries", &primitive.Procedure{F: directoryEntriesFn, Help: helpMap["directory:entries"]})
 	env.Set("directory?", &primitive.Procedure{F: directoryFn, Help: helpMap["directory?"], Args: []primitive.Symbol{primitive.Symbol("path")}})
+	env.Set("env", &primitive.Procedure{F: envFn, Help: helpMap["env"], Args: []primitive.Symbol{}})
 	env.Set("eq", &primitive.Procedure{F: eqFn, Help: helpMap["eq"], Args: []primitive.Symbol{primitive.Symbol("a"), primitive.Symbol("b")}})
 	env.Set("error", &primitive.Procedure{F: errorFn, Help: helpMap["error"], Args: []primitive.Symbol{primitive.Symbol("message")}})
 	env.Set("exists?", &primitive.Procedure{F: existsFn, Help: helpMap["exists?"], Args: []primitive.Symbol{primitive.Symbol("path")}})
@@ -458,6 +459,34 @@ func divideFn(env *env.Environment, args []primitive.Primitive) primitive.Primit
 	return primitive.Number(v)
 }
 
+// envFn returns registered "things" from our environment
+func envFn(env *env.Environment, args []primitive.Primitive) primitive.Primitive {
+	// create a new list
+	var c primitive.List
+
+	for key, val := range env.Items() {
+
+		v := val.(primitive.Primitive)
+
+		tmp := primitive.NewHash()
+		tmp.Set(":name", primitive.String(key))
+		tmp.Set(":value", v)
+
+		// Is this a procedure?  If so
+		// add the help-text
+		proc, ok := v.(*primitive.Procedure)
+		if ok {
+			if len(proc.Help) > 0 {
+				tmp.Set(":help", primitive.String(proc.Help))
+			}
+		}
+
+		c = append(c, tmp)
+	}
+
+	return c
+}
+
 // eqFn implements "eq"
 func eqFn(env *env.Environment, args []primitive.Primitive) primitive.Primitive {
 	if len(args) != 2 {
diff --git a/builtins/builtins_test.go b/builtins/builtins_test.go
index 9277328..4f341d6 100644
--- a/builtins/builtins_test.go
+++ b/builtins/builtins_test.go
@@ -944,6 +944,44 @@ func TestEnsureHelpPresent(t *testing.T) {
 	}
 }
 
+// TestEnv tests env
+func TestEnv(t *testing.T) {
+
+	// Load our standard library
+	st := stdlib.Contents()
+	std := string(st)
+
+	// Create a new interpreter
+	l := eval.New(std + "\n")
+
+	env := env.New()
+	l.Evaluate(env)
+
+	// No arguments
+	out := envFn(env, []primitive.Primitive{})
+
+	// Will lead to a list
+	e, ok := out.(primitive.List)
+	if !ok {
+		t.Fatalf("expected list, got %v", out)
+	}
+
+	// Ensure our list of items contains only hashes.
+	for _, x := range e {
+
+		// Get the hash
+		_, ok2 := x.(primitive.Hash)
+		if !ok2 {
+			t.Fatalf("env should have a list of hashes, found element %v", x)
+		}
+
+	}
+
+	if len(e) < 100 {
+		t.Fatalf("expected a lot of entries, got %d", len(e))
+	}
+}
+
 // TestEq tests "eq" (non-numerical equality)
 func TestEq(t *testing.T) {
 
diff --git a/builtins/help.txt b/builtins/help.txt
index 2b09644..a5b11fc 100644
--- a/builtins/help.txt
+++ b/builtins/help.txt
@@ -105,6 +105,10 @@ path, recursively.  It is a helper function used to implement directory:walk
 
 See also: directory:walk, glob
 %%
+env
+
+env returns all the registered symbols from the environment, as a list of hashes.
+%%
 eq
 
 eq returns true if the two values supplied as parameters have the same type, and string representation.
diff --git a/eval/specials.go b/eval/specials.go
index ead0849..ee92dfc 100644
--- a/eval/specials.go
+++ b/eval/specials.go
@@ -90,33 +90,6 @@ func (ev *Eval) evalSpecialForm(name string, args []primitive.Primitive, e *env.
 		}
 		return ret, true
 
-	case "env":
-
-		// create a new list
-		var c primitive.List
-
-		for key, val := range e.Items() {
-
-			v := val.(primitive.Primitive)
-
-			tmp := primitive.NewHash()
-			tmp.Set(":name", primitive.String(key))
-			tmp.Set(":value", v)
-
-			// Is this a procedure?  If so
-			// add the help-text
-			proc, ok := v.(*primitive.Procedure)
-			if ok {
-				if len(proc.Help) > 0 {
-					tmp.Set(":help", primitive.String(proc.Help))
-				}
-			}
-
-			c = append(c, tmp)
-		}
-
-		return c, true
-
 	case "eval":
 		if len(args) != 1 {
 			return primitive.ArityError(), true