1 files changed, 0 insertions, 259 deletions
diff --git a/doc/talks/io2010/eval2.go b/doc/talks/io2010/eval2.go
deleted file mode 100644
index 6f826e12d..000000000
--- a/doc/talks/io2010/eval2.go
+++ /dev/null
@@ -1,259 +0,0 @@
-// Copyright 2010 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package main
-
-import (
-	"bufio"
-	"fmt"
-	"os"
-	"strconv"
-	"strings"
-)
-
-// Generic expression parser/evaluator
-
-type Value interface {
-	String() string
-	BinaryOp(op string, y Value) Value
-}
-
-type Parser struct {
-	precTab map[string]int
-	newVal  func(string) Value
-	src     string
-	pos     int
-	tok     string
-}
-
-const alphanum = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
-
-func (p *Parser) stop(c uint8) bool {
-	switch {
-	case p.pos >= len(p.src):
-		return true
-	case c == '"':
-		if p.src[p.pos] == '"' {
-			p.pos++
-			return true
-		}
-		return false
-	case strings.IndexRune(alphanum, int(c)) >= 0:
-		return strings.IndexRune(alphanum, int(p.src[p.pos])) < 0
-	}
-	return true
-}
-
-func (p *Parser) next() {
-	// skip blanks
-	for ; p.pos < len(p.src) && p.src[p.pos] <= ' '; p.pos++ {
-	}
-	if p.pos >= len(p.src) {
-		p.tok = ""
-		return
-	}
-	start := p.pos
-	c := p.src[p.pos]
-	for p.pos < len(p.src) {
-		p.pos++
-		if p.stop(c) {
-			break
-		}
-	}
-	p.tok = p.src[start:p.pos]
-}
-
-func (p *Parser) binaryExpr(prec1 int) Value {
-	x := p.newVal(p.tok)
-	p.next()
-	for prec := p.precTab[p.tok]; prec >= prec1; prec-- {
-		for p.precTab[p.tok] == prec {
-			op := p.tok
-			p.next()
-			y := p.binaryExpr(prec + 1)
-			x = x.BinaryOp(op, y)
-		}
-	}
-	return x
-}
-
-func Eval(precTab map[string]int, newVal func(string) Value, src string) Value {
-	var p Parser
-	p.precTab = precTab
-	p.newVal = newVal
-	p.src = src
-	p.next()
-	return p.binaryExpr(1)
-}
-
-// Command-line expression evaluator
-
-func main() {
-	r := bufio.NewReader(os.Stdin)
-	for {
-		fmt.Printf("> ")
-		line, err := r.ReadString('\n')
-		if err != nil {
-			break
-		}
-		fmt.Printf("%s\n", Eval(precTab, trace(newVal), line))
-	}
-}
-
-// Custom grammar and values
-
-var precTab = map[string]int{
-	"&&": 1,
-	"||": 2,
-	"==": 3,
-	"!=": 3,
-	"<":  3,
-	"<=": 3,
-	">":  3,
-	">=": 3,
-	"+":  4,
-	"-":  4,
-	"*":  5,
-	"/":  5,
-	"%":  5,
-}
-
-func newVal(lit string) Value {
-	x, err := strconv.Atoi(lit)
-	if err == nil {
-		return Int(x)
-	}
-	b, err := strconv.ParseBool(lit)
-	if err == nil {
-		return Bool(b)
-	}
-	s, err := strconv.Unquote(lit)
-	if err == nil {
-		return String(s)
-	}
-	return Error(fmt.Sprintf("illegal literal '%s'", lit))
-}
-
-type Error string
-
-func (e Error) String() string                    { return string(e) }
-func (e Error) BinaryOp(op string, y Value) Value { return e }
-
-type Int int
-
-func (x Int) String() string { return strconv.Itoa(int(x)) }
-func (x Int) BinaryOp(op string, y Value) Value {
-	switch y := y.(type) {
-	case Error:
-		return y
-	case String:
-		switch op {
-		case "*":
-			return String(strings.Repeat(string(y), int(x)))
-		}
-	case Int:
-		switch op {
-		case "+":
-			return x + y
-		case "-":
-			return x - y
-		case "*":
-			return x * y
-		case "/":
-			return x / y
-		case "%":
-			return x % y
-		case "==":
-			return Bool(x == y)
-		case "!=":
-			return Bool(x != y)
-		case "<":
-			return Bool(x < y)
-		case "<=":
-			return Bool(x <= y)
-		case ">":
-			return Bool(x > y)
-		case ">=":
-			return Bool(x >= y)
-		}
-	}
-	return Error(fmt.Sprintf("illegal operation: '%v %s %v'", x, op, y))
-}
-
-type Bool bool
-
-func (x Bool) String() string { return strconv.FormatBool(bool(x)) }
-func (x Bool) BinaryOp(op string, y Value) Value {
-	switch y := y.(type) {
-	case Error:
-		return y
-	case Bool:
-		switch op {
-		case "&&":
-			return Bool(x && y)
-		case "||":
-			return Bool(x || y)
-		case "==":
-			return Bool(x == y)
-		case "!=":
-			return Bool(x != y)
-		}
-	}
-	return Error(fmt.Sprintf("illegal operation: '%v %s %v'", x, op, y))
-}
-
-type String string
-
-func (x String) String() string { return strconv.Quote(string(x)) }
-func (x String) BinaryOp(op string, y Value) Value {
-	switch y := y.(type) {
-	case Error:
-		return y
-	case Int:
-		switch op {
-		case "*":
-			return String(strings.Repeat(string(x), int(y)))
-		}
-	case String:
-		switch op {
-		case "+":
-			return x + y
-		case "<":
-			return Bool(x < y)
-		}
-	}
-	return Error(fmt.Sprintf("illegal operation: '%v %s %v'", x, op, y))
-}
-
-func trace(newVal func(string) Value) func(string) Value {
-	return func(s string) Value {
-		v := newVal(s)
-		fmt.Printf("\tnewVal(%q) = %s\n", s, fmtv(v))
-		return &traceValue{v}
-	}
-}
-
-type traceValue struct {
-	Value
-}
-
-func (x *traceValue) BinaryOp(op string, y Value) Value {
-	z := x.Value.BinaryOp(op, y.(*traceValue).Value)
-	fmt.Printf("\t%s.BinaryOp(%q, %s) = %s\n", fmtv(x.Value), op, fmtv(y.(*traceValue).Value), fmtv(z))
-	return &traceValue{z}
-}
-
-func (x *traceValue) String() string {
-	s := x.Value.String()
-	fmt.Printf("\t%s.String() = %#v\n", fmtv(x.Value), s)
-	return s
-}
-
-func fmtv(v Value) string {
-	t := fmt.Sprintf("%T", v)
-	if i := strings.LastIndex(t, "."); i >= 0 { // strip package
-		t = t[i+1:]
-	}
-	return fmt.Sprintf("%s(%#v)", t, v)
-}