From d3660c578700ae158f6cd89c097eec7b8c391c4a Mon Sep 17 00:00:00 2001
From: Linus Lee <linus@thesephist.com>
Date: Sun, 23 Feb 2020 21:27:35 -0500
Subject: [PATCH] Represent proxy values in repl as their underlying values

---
 pkg/xin/lib.go     |  1 +
 pkg/xin/map.go     | 16 ++++++++++++----
 pkg/xin/reader.go  |  8 ++++++++
 pkg/xin/runtime.go |  5 ++---
 pkg/xin/value.go   |  7 +++++++
 pkg/xin/vec.go     |  6 +++++-
 6 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/pkg/xin/lib.go b/pkg/xin/lib.go
index 8b4994e..eb3a1dd 100644
--- a/pkg/xin/lib.go
+++ b/pkg/xin/lib.go
@@ -25,6 +25,7 @@ func loadStandardLibrary(vm *Vm) InterpreterError {
 		"str",
 		"src",
 		"stat",
+		"os",
 		"test",
 	}
 
diff --git a/pkg/xin/map.go b/pkg/xin/map.go
index ba26a53..03b00bc 100644
--- a/pkg/xin/map.go
+++ b/pkg/xin/map.go
@@ -1,16 +1,20 @@
 package xin
 
+import (
+	"strings"
+)
+
 // StringValue is of type []byte, which is unhashable
 // so we convert StringValues to hashable string type
 // before using as map keys
 type hashableStringProxy string
 
 func (v hashableStringProxy) String() string {
-	return "(<string (proxy)> " + string(v) + ")"
+	return string(v)
 }
 
 func (v hashableStringProxy) Repr() string {
-	return v.String()
+	return "'" + strings.ReplaceAll(string(v), "'", "\\'") + "'"
 }
 
 func (v hashableStringProxy) Equal(ov Value) bool {
@@ -22,7 +26,7 @@ func (v hashableStringProxy) Equal(ov Value) bool {
 type hashableNativeFormProxy string
 
 func (v hashableNativeFormProxy) String() string {
-	return "(<native form (proxy)> " + string(v) + ")"
+	return "(<native form> " + string(v) + ")"
 }
 
 func (v hashableNativeFormProxy) Repr() string {
@@ -76,7 +80,11 @@ func (v MapValue) String() string {
 }
 
 func (v MapValue) Repr() string {
-	return v.String()
+	ss := ""
+	for k, val := range *v.items {
+		ss += " " + k.Repr() + "->" + val.Repr()
+	}
+	return "(<map>" + ss + ")"
 }
 
 func (v MapValue) Equal(o Value) bool {
diff --git a/pkg/xin/reader.go b/pkg/xin/reader.go
index 09fd55d..ba1d473 100644
--- a/pkg/xin/reader.go
+++ b/pkg/xin/reader.go
@@ -3,6 +3,7 @@ package xin
 import (
 	"io"
 	"io/ioutil"
+	"strings"
 )
 
 type reader struct {
@@ -25,6 +26,13 @@ func newReader(path string, r io.Reader) (*reader, error) {
 		max:    len(asString),
 	}
 	rdr.position.path = path
+
+	// read shebang line if present
+	if strings.HasPrefix(asString, "#!") {
+		rdr.upto("\n")
+		rdr.skip()
+	}
+
 	return &rdr, nil
 }
 func (rdr *reader) done() bool {
diff --git a/pkg/xin/runtime.go b/pkg/xin/runtime.go
index e78947a..646abc7 100644
--- a/pkg/xin/runtime.go
+++ b/pkg/xin/runtime.go
@@ -2,7 +2,6 @@ package xin
 
 import (
 	"bufio"
-	"fmt"
 	"io"
 	"math"
 	"math/rand"
@@ -19,7 +18,7 @@ type NativeFormValue struct {
 }
 
 func (v NativeFormValue) String() string {
-	return fmt.Sprintf("(<native form> %s)", v.name)
+	return "(<native form> " + v.name + ")"
 }
 
 func (v NativeFormValue) Repr() string {
@@ -39,7 +38,7 @@ func loadAllDefaultValues(vm *Vm) {
 
 	stdoutStream := NewStream()
 	stdoutStream.callbacks.sink = func(v Value) InterpreterError {
-		fmt.Printf(v.String())
+		os.Stdout.Write([]byte(v.String()))
 		return nil
 	}
 	fr.Put("os::stdout", stdoutStream)
diff --git a/pkg/xin/value.go b/pkg/xin/value.go
index d2d0d84..a12810f 100644
--- a/pkg/xin/value.go
+++ b/pkg/xin/value.go
@@ -14,8 +14,15 @@ import (
 // 	exception to this case, where a proxy Value type is used instead
 // 	which is hashable.
 type Value interface {
+	// String is stable, string representation of a Xin value
+	// that can be used to back the to-string type conversion of values
 	String() string
+
+	// Repr is an unstable, human-readable representation of Xin values used for
+	// debugging and the repl, should not be considered a stable API
+	// to be used in the language internally.
 	Repr() string
+
 	Equal(Value) bool
 }
 
diff --git a/pkg/xin/vec.go b/pkg/xin/vec.go
index 727a2cf..e079f36 100644
--- a/pkg/xin/vec.go
+++ b/pkg/xin/vec.go
@@ -28,7 +28,11 @@ func (v VecValue) String() string {
 }
 
 func (v VecValue) Repr() string {
-	return v.String()
+	ss := ""
+	for _, item := range v.underlying.items {
+		ss += " " + item.Repr()
+	}
+	return "(<vec>" + ss + ")"
 }
 
 func (v VecValue) Equal(o Value) bool {