From cc5fba63c5ab4f422a54891d35890ee12d5e646c Mon Sep 17 00:00:00 2001
From: Michael Aaron Murphy <mmstickman@gmail.com>
Date: Sun, 1 Oct 2017 10:01:11 -0400
Subject: [PATCH] Implement PROMPT Function Support To use a function to
generate a prompt, simply create a function whose name is PROMPT.
---
manual/src/ch02-00-features.md | 66 -----------------------------
manual/src/ch03-00-miscellaneous.md | 1 +
manual/src/ch03-07-prompt_fn.md | 13 ++++++
src/shell/binary.rs | 62 +++++++++++++++++++++++----
4 files changed, 68 insertions(+), 74 deletions(-)
create mode 100644 manual/src/ch03-07-prompt_fn.md
diff --git a/manual/src/ch02-00-features.md b/manual/src/ch02-00-features.md
index 42b7df3c..6b110878 100644
--- a/manual/src/ch02-00-features.md
+++ b/manual/src/ch02-00-features.md
@@ -1,71 +1,5 @@
# Features
-Below is an overview of features that Ion has either already implemented, or aims to implement in
-the future. If you have any ideas for features that Ion hasn't considered, you are welcome to
-open an issue on the project's GitHub.
-
-- Misc
- - [x] Implicit `cd`
- - [x] XDG App Dirs
-- Variables
- - [x] String Variables
- - [x] Array Variables
- - [x] Aliases
- - [ ] Associative Arrays
-- Shell Expansions
- - Variable Expansions
- - [x] String Expansions (**$string**, **${string}**)
- - [x] Array Expansions (**@array**, **@{array}**)
- - Process Expansions
- - [x] String Process Expansions (**$(command args...)**)
- - [x] Array Process Expansions (**@(command args...)**)
- - Brace Expansions (**abc{1,2,3}def{1,2,3}ghi**)
- - [x] Brace Ranges
- - [x] Nested Braces
- - [x] Permutated Braces
- - [x] Arithmetic Expansions (**$((5 * 10 / 3.5))**)
- - Method Expansions
- - [x] String Methods (**$method(args...)**)
- - [x] Array Methods (**@method(args...)**)
- - [x] Inline Methods (Expressions Within Methods)
-- Slicing Syntax
- - [x] String Variable Slicing (**$string[5..10]**)
- - [x] Array Variable Slicing (**@array[5..10]**)
- - [x] Array Slicing (**[one two three][2]**)
- - [x] String Process Slicing (**$(command args...)[15..]**)
- - [x] Array Process Slicing (**@(command args...)[1]**)
- - [x] Exclusive Ranges (**N..N**)
- - [x] Inclusive Ranges (**N...N**)
-- Control Flow
- - [x] For Loops
- - [x] While Loops
- - [x] If Statements
- - [x] Match Statements (Incomplete)
- - [ ] Match All Statements
- - [ ] For Match Loop
- - [ ] Foreach Loops
-- Functions
- - [x] Optionally-Typed Function Parameters
- - [x] Descriptions
- - [ ] Local Scopes & Dynamic Variables
- - [ ] Piping / Redirecting Functions
- - [ ] Backgrounding Functions
- - [ ] Execute Function When Variable Changes
-- Builtin Commands
- - [ ] Piping / Redirecting Builtins
- - [ ] Implemented All Builtins
- - [ ] Completed Help Documentation
-- [x] Script Executions
-- [x] Signal Handling
-- Job Control
- - [x] `bg`, `fg`, `jobs`, etc.
- - [x] Send jobs to background with **&**
-- Plugins Support
- - [ ] Builtin Plugins
- - [ ] Prompt Plugins
- - [ ] Syntax Plugins
-
-
## Miscellanious Features
Small features that don't belong in any specific category.
diff --git a/manual/src/ch03-00-miscellaneous.md b/manual/src/ch03-00-miscellaneous.md
index d461dd8d..b7e14a9f 100644
--- a/manual/src/ch03-00-miscellaneous.md
+++ b/manual/src/ch03-00-miscellaneous.md
@@ -8,3 +8,4 @@ These are features of Ion that don't belong to any specific category:
- [Multi-line Arguments](ch03-04-multiargs.html)
- [Multi-line Comments](ch03-05-multicomments.html)
- [General Tips](ch03-06-general.html)
+- [Prompt Function](ch03-07-prompt_fn.html)
diff --git a/manual/src/ch03-07-prompt_fn.md b/manual/src/ch03-07-prompt_fn.md
new file mode 100644
index 00000000..79605d6f
--- /dev/null
+++ b/manual/src/ch03-07-prompt_fn.md
@@ -0,0 +1,13 @@
+# Prompt Function
+
+The prompt may optionally be generated from a function, instead of a string. Take note, however,
+that prompts generated from functions aren't as efficient, due to the need to perform a fork and
+capture the output of the fork to use as the prompt. To use a function for generating the prompt,
+simply create a function whose name is **PROMPT**, and the output of that command will be used as
+the prompt. Below is an example:
+
+```
+fn PROMPT
+ echo -n "${PWD}# "
+end
+```
diff --git a/src/shell/binary.rs b/src/shell/binary.rs
index 4af818e1..361ef8ac 100644
--- a/src/shell/binary.rs
+++ b/src/shell/binary.rs
@@ -12,11 +12,13 @@ use smallstring::SmallString;
use smallvec::SmallVec;
use std::env;
use std::fs::File;
-use std::io::{self, ErrorKind, Write};
+use std::io::{self, ErrorKind, Read, Write};
use std::iter::{self, FromIterator};
use std::mem;
+use std::os::unix::io::FromRawFd;
use std::path::{Path, PathBuf};
use std::process;
+use std::process::exit;
use sys;
use types::*;
@@ -36,28 +38,68 @@ pub(crate) trait Binary {
/// rendering, controlling, and getting input from the prompt.
fn readln(&mut self) -> Option<String>;
/// Generates the prompt that will be used by Liner.
- fn prompt(&self) -> String;
+ fn prompt(&mut self) -> String;
/// Display version information and exit
fn display_version(&self);
+ // Executes the PROMPT function, if it exists, and returns the output.
+ fn prompt_fn(&mut self) -> Option<String>;
}
impl<'a> Binary for Shell<'a> {
- fn prompt(&self) -> String {
+ fn prompt(&mut self) -> String {
if self.flow_control.level == 0 {
- let prompt_var = self.variables.get_var_or_empty("PROMPT");
- expand_string(&prompt_var, self, false).join(" ")
+ let rprompt = match self.prompt_fn() {
+ Some(prompt) => prompt,
+ None => self.variables.get_var_or_empty("PROMPT"),
+ };
+ expand_string(&rprompt, self, false).join(" ")
} else {
" ".repeat(self.flow_control.level as usize)
}
}
+ fn prompt_fn(&mut self) -> Option<String> {
+ let function = match self.functions.get("PROMPT") {
+ Some(func) => func.clone(),
+ None => return None,
+ };
+
+ let (read_fd, write_fd) = match sys::pipe2(0) {
+ Ok(fds) => fds,
+ Err(why) => {
+ eprintln!("ion: unable to create pipe: {}", why);
+ return None;
+ }
+ };
+
+ match unsafe { sys::fork() } {
+ Ok(0) => {
+ let _ = sys::dup2(write_fd, sys::STDOUT_FILENO);
+ let _ = sys::close(read_fd);
+ let _ = sys::close(write_fd);
+ let _ = function.execute(self, &["ion"]);
+ exit(0);
+ }
+ Ok(_) => {
+ let _ = sys::close(write_fd);
+ let mut child_stdout = unsafe { File::from_raw_fd(read_fd) };
+ let mut output = String::new();
+ let _ = child_stdout.read_to_string(&mut output);
+ Some(output)
+ }
+ Err(why) => {
+ let _ = sys::close(read_fd);
+ let _ = sys::close(write_fd);
+ eprintln!("ion: fork error: {}", why);
+ None
+ }
+ }
+ }
+
fn readln(&mut self) -> Option<String> {
{
let vars_ptr = &self.variables as *const Variables;
let dirs_ptr = &self.directory_stack as *const DirectoryStack;
- let funcs = &self.functions;
- let vars = &self.variables;
- let builtins = self.builtins;
// Collects the current list of values from history for completion.
let history = &self.context.as_ref().unwrap().history.buffers.iter()
@@ -68,6 +110,10 @@ impl<'a> Binary for Shell<'a> {
loop {
let prompt = self.prompt();
+ let funcs = &self.functions;
+ let vars = &self.variables;
+ let builtins = self.builtins;
+
let line = self.context.as_mut().unwrap().read_line(
prompt,
&mut move |Event {
--
GitLab