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nums/main.go

367 lines
7.5 KiB
Go

// nums, a postfix cli calculator
//
// Copyright © 2021 sloum < sloum@rawtext.club >
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
package main
import (
"flag"
"fmt"
"io/ioutil"
"math"
"os"
"strconv"
"strings"
"tildegit.org/sloum/nums/qline"
"tildegit.org/sloum/nums/termios"
)
const (
add int = iota
sub
mul
div
pow
rnd
flr
cil
abs
inv
sqt
)
type stack struct {
ptr int
data [100]float64
}
func (s *stack) Push(v float64) {
if s.ptr >= 99 {
PrintError("Stack overflow")
s.Clear()
return
}
s.ptr++
s.data[s.ptr] = v
}
func (s *stack) Pop() (float64, error) {
if s.ptr < 0 {
PrintError("Stack underflow")
s.Clear()
return 0.0, fmt.Errorf("Stack underflow")
}
s.ptr--
return s.data[s.ptr+1], nil
}
func (s *stack) Clear() {
s.ptr = -1
}
func (s stack) Len() int {
return s.ptr+1
}
func (s *stack) Add() {
n2, err := s.Pop()
if err != nil {
return
}
n1, err := s.Pop()
if err != nil {
return
}
s.Push(n1+n2)
}
func (s *stack) Sub() {
n2, err := s.Pop()
if err != nil {
return
}
n1, err := s.Pop()
if err != nil {
return
}
s.Push(n1-n2)
}
func (s *stack) Mul() {
n2, err := s.Pop()
if err != nil {
return
}
n1, err := s.Pop()
if err != nil {
return
}
s.Push(n1*n2)
}
func (s *stack) Div() {
n2, err := s.Pop()
if err != nil {
return
}
n1, err := s.Pop()
if err != nil {
return
}
s.Push(n1/n2)
}
func (s *stack) Pow() {
exp, err := s.Pop()
if err != nil {
return
}
base, err := s.Pop()
if err != nil {
return
}
s.Push(math.Pow(base, exp))
}
func (s *stack) Floor() {
n, err := s.Pop()
if err != nil {
return
}
s.Push(math.Floor(n))
}
func (s *stack) Ceil() {
n, err := s.Pop()
if err != nil {
return
}
s.Push(math.Ceil(n))
}
func (s *stack) Round() {
decimals, err := s.Pop()
if err != nil {
return
}
num, err := s.Pop()
if err != nil {
return
}
s.Push(math.Round(num*math.Pow(10, decimals)) / math.Pow(10, decimals))
}
func (s *stack) Abs() {
n, err := s.Pop()
if err != nil {
return
}
if n < 0 {
s.Push(n*-1)
} else {
s.Push(n)
}
}
func (s *stack) Inv() {
n, err := s.Pop()
if err != nil {
return
}
s.Push(n*-1)
}
func (s *stack) Sqt() {
n, err := s.Pop()
if err != nil {
return
}
s.Push(math.Sqrt(n))
}
func (s *stack) Dup() {
val, err := s.Pop()
if err != nil {
return
}
s.Push(val)
s.Push(val)
}
func (s *stack) Ovr() {
tos, err := s.Pop()
if err != nil {
return
}
cpy, err := s.Pop()
if err != nil {
return
}
s.Push(cpy)
s.Push(tos)
s.Push(cpy)
}
func (s *stack) Swp() {
tos, err := s.Pop()
if err != nil {
return
}
newTos, err := s.Pop()
if err != nil {
return
}
s.Push(tos)
s.Push(newTos)
}
func (s *stack) Drp() {
s.Pop()
}
func (s stack) TOS() string {
if s.ptr < 0 {
return "0"
}
return strconv.FormatFloat(s.data[s.ptr], 'f', -1, 64)
}
func PrintError(s string) {
fmt.Fprintf(os.Stderr, "\033[1;91m[Err] %s,\033[0m\n", s)
}
func PrintOperatorHelp() {
txt := `# General
This calculator uses reverse polish notation. As such, the operators come after the operands. For example:
5 7 + 1 -
The output of the above would be '11' (using infix notation this would be written ' 5 + 7 - 1'). For more information on reverse polish notation see: https://en.wikipedia.org/wiki/Reverse_Polish_notation
The output of a calculation will always be the top of the stack. If there is more than one value on the stack at the end of a calculation a warning will be output to stderr.
# Command List
The following commands all have a three character version and a single character version. Either one is valid. They are displayed as a comma separated values (single character version first) followed by a colon and a description of the operator. The operators are case insensitive.
+, add: Adds the top two values on the stack
-, sub: Subtracts the top stack value from the value underneath it
/, div: Divides the top two stack values with the top of stack being the divisor and the value below it on the stack being the dividend
*, mul: Multiplies the top two values on the stack
^, pow: Raises the value underneath top of stack to the power of top of stack
@, rnd: Rounds the value underneath top of stack to the number of decimal places represented by top of stack. If top of stack is not a whole number an error will result
>, cil: Performs a ceiling function on the top of stack (rounds it up to the next whole number)
<, flr: Performs a floor function on the top of stack (rounds it down to the next whole number)
|, abs: Takes the top value from the stack and leaves its absolute value
!, inv: Multiplies top of stack by -1
V, sqt: Takes the top value from the stack and leaves its square root
The following commands operate on the stack, rather than as numerical operations:
x, swp: Swap the position of the top two values on the stack
#, dup: Duplicate/copy the value on top of the stack such that the copy is now above the original on the stack
_, clr: Clear the stack (wipe out all values and start over)
., drp: Drop the top value on the stack (remove it and throw it away)
?, help: Prints this help message
`
fmt.Fprintf(os.Stderr, "%s\033\n", txt)
}
func processWord(w string, s *stack) {
num, err := strconv.ParseFloat(w, 64)
if err == nil {
s.Push(num)
return
}
w = strings.ToLower(w)
switch w {
case "+", "add":
s.Add()
case "-", "sub":
s.Sub()
case "*", "mul":
s.Mul()
case "/", "div":
s.Div()
case "^", "pow":
s.Pow()
case "@", "rnd":
s.Round()
case ">", "cil":
s.Ceil()
case "<", "flr":
s.Floor()
case "|", "abs":
s.Abs()
case "!", "inv":
s.Inv()
case "V", "sqt":
s.Sqt()
case "#", "dup":
s.Dup()
case "x", "swp":
s.Swp()
case "_", "clr":
s.Clear()
case ".", "drp":
s.Drp()
case "?", "help":
PrintOperatorHelp()
s.Clear()
default:
PrintError(fmt.Sprintf("Unknown operator: %q", w))
s.Clear()
}
}
func main() {
pipe := flag.Bool("p", false, "Take input from a pipe")
flag.Parse()
s := stack{-1, [100]float64{}}
if !*pipe {
termios.SetInitialTermios()
defer termios.Restore()
termios.SetCharMode()
for {
var cols, _ = termios.GetWindowSize()
ln := qline.GetInput("", "", cols)
f := strings.Fields(ln)
if len(f) == 0 {
break
}
fmt.Print("\n")
for _, val := range f {
processWord(val, &s)
}
fmt.Fprintf(os.Stderr, "%v\n", s.data[:s.ptr+1])
}
} else {
b, err := ioutil.ReadAll(os.Stdin)
if err != nil {
fmt.Fprint(os.Stderr, "Unable to read from pipe")
}
f := strings.Fields(string(b))
for _, val := range f {
processWord(val, &s)
}
if s.ptr >= 0 {
fmt.Fprintf(os.Stderr, "%v\n", s.data[s.ptr])
} else {
os.Exit(1)
}
}
}