From b062be2ccbb7c5bfac71818193994474a6ced8de Mon Sep 17 00:00:00 2001
From: Antoine COMBET <antoine.combet@etu.univ-lyon1.fr>
Date: Thu, 4 Nov 2021 21:39:25 +0100
Subject: [PATCH] Did the program and its manpage

---
 todo   | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 todo.1 | 38 +++++++++++++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100755 todo
 create mode 100644 todo.1

diff --git a/todo b/todo
new file mode 100755
index 0000000..49bee41
--- /dev/null
+++ b/todo
@@ -0,0 +1,90 @@
+#!/usr/bin/env lua
+
+local usage = function(stream)
+    stream:write(arg[0] .. [[ -- manage a todo stack
+todo pop
+todo peek
+todo push <task>
+
+for more info see `man todo.1`
+]])
+end
+
+local peek = function(stack)
+    if #stack == 0 then os.exit(2) end
+    io.write(stack[#stack])
+    io.write("\n")
+    return stack
+end
+
+local pop = function(stack)
+    peek(stack)
+    stack[#stack] = nil
+    return stack
+end
+
+local push = function(stack, args)
+    if not args[2] then
+        io.stderr:write("Invalid syntax\nUsage:\n")
+        usage(io.stderr)
+        os.exit(1)
+    end
+    stack[#stack + 1] = args[2]
+    return stack
+end
+
+local exists = function(path)
+    return os.rename(path,path) or false
+end
+
+local read_stack = function(path)
+    local f = io.open(path, "r")
+    if not f then os.exit(1) end
+    local t = {}
+    for l in f:lines() do
+        t[#t + 1] = l
+    end
+    f:close()
+    return t
+end
+
+local write_stack = function(path, stack)
+    local f = io.open(path, "w")
+    if not f then os.exit(1) end
+    for _, v in ipairs(stack) do
+        f:write(v)
+        f:write("\n")
+    end
+    f:close()
+end
+
+local stack_path = os.getenv("HOME") .. "/.local/share/todostack"
+
+if not exists(stack_path) then
+    local f = io.open(stack_path, "w")
+    f:close()
+end
+
+local commands = {
+        peek = peek,
+        pop = pop,
+        push = push,
+        help = function()
+            usage(io.stdout)
+        end
+    }
+
+local c = commands[arg[1]]
+if not c then
+    if arg[1] then
+        io.stderr:write("unknown command: " .. arg[1] .. "\nUsage:\n")
+    else
+        io.stderr:write("Please specify a command\n Usage:\n")
+    end
+    usage(io.stderr)
+    os.exit(1)
+else
+    local stack = read_stack(stack_path)
+    stack = c(stack, arg)
+    write_stack(stack_path, stack)
+end
diff --git a/todo.1 b/todo.1
new file mode 100644
index 0000000..9b648af
--- /dev/null
+++ b/todo.1
@@ -0,0 +1,38 @@
+.\" Man page for the todo utility ./todo.1
+.TH TODO 1
+
+.SH NAME
+todo \- manages a todo stack
+.SH SYNOPSIS
+.B todo
+.IR command " [" option "]"
+.SH DESCRIPTION
+.P
+.B todo
+is a small utility to manage a todo stack. It can push onto the stack, read the top element, and pop the top element.
+.SH OPTIONS
+.TP
+.BI push " task"
+Pushes a new task on the user's todo stack.
+.TP
+.B peek
+Outputs the task at the top of the stack.
+Does not alter the stack.
+.TP
+.B pop
+Outputs the task at the top of the stack, then pops it off.
+.SH EXIT STATUS
+.TP
+.B 0
+Operation successful.
+.TP
+.B 1
+General error
+.TP
+.B 2
+Todo stack underflow on a \fBpop\fR command or a \fBpeek\fR command.
+.SH FILES
+.TP
+.B $HOME/.local/share/todostack
+The user's todo stack.
+.SH