From 5293810b79fb52c10125ce21ada2a8eb09ac0474 Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Tue, 18 Mar 2025 15:02:40 +0000
Subject: [PATCH] Added `--write-only` & `--no-consume` for when loading a
 chain is all that"s desired. Added 0 line output (default is still 1) for if
 saving/modifying a chain is all that"s desired.
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Bumped version.

Fortune for genmarkov's current commit: Middle blessing − 中吉
---
 Cargo.lock  |  2 +-
 Cargo.toml  |  6 +++---
 src/main.rs | 51 +++++++++++++++++++++++++++++++--------------------
 3 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 0bbbac8..8b86caa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -388,7 +388,7 @@ checksum = "8dd5a6d5999d9907cda8ed67bbd137d3af8085216c2ac62de5be860bd41f304a"
 
 [[package]]
 name = "markov"
-version = "0.2.1+1"
+version = "0.2.2"
 dependencies = [
  "async-compression",
  "bytes",
diff --git a/Cargo.toml b/Cargo.toml
index 6de0a65..996eebd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "markov"
-version = "0.2.1+1"
+version = "0.2.2"
 description = "Generate string of text from Markov chain fed by stdin or file(s)"
 authors = ["Avril <flanchan@cumallover.me>"]
 edition = "2018"
@@ -20,10 +20,10 @@ lto = "fat"
 strip = false
 
 [features]
-default = ["threads", "io_uring"]
+default = ["threads"]
 
 threads = ["zstd/zstdmt", "dep:num_cpus"]
-io_uring = ["dep:tokio-uring", "dep:async-compression", "dep:futures", "dep:tokio"]
+#io_uring = ["dep:tokio-uring", "dep:async-compression", "dep:futures", "dep:tokio"]
 
 [dependencies]
 async-compression = { version = "0.4.18", features = ["tokio", "zstd", "zstdmt"], optional = true }
diff --git a/src/main.rs b/src/main.rs
index abb757a..7e779a9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -25,15 +25,24 @@ pub struct Cli {
     save: Option<PathBuf>,
     /// Load the chain from the provided output file name before appending to it.
     #[arg(short, long)]
-    load: Option<PathBuf>,
+    load: Option<PathBuf>, // TODO: Group with `save` & add `-F/--file` opt for save & load from same file.
     /// Force over-writes of files, and force output of binary data to TTY.
     #[arg(short, long)]
     force: bool,
 
-    /// The number of lines to output from the chain.
-    lines: Option<NonZeroUsize>, // TODO: Allow 0 for only save + load operations.
+    /// Do not read into chain from `stdin` if there is a loaded chain that is not empty.
+    #[arg(short, long)]
+    no_consume: bool,
+
+    /// Do not read into chain from `stdin` ever.
+    #[arg(short, long="write")]
+    write_only: bool, // XXX: Should we group this with `no_consume`?
 
-    //TODO: Num of lines, etc.
+    /// The number of lines to output from the chain. Default is 1.
+    ///
+    /// If 0, generation from chain is skipped.
+    #[arg(default_value_t = 1)]
+    lines: usize,
 }
 
 fn buffered_read_all_lines<T: BufRead+?Sized, F: FnMut(&str) -> io::Result<()>>(input: &mut T, mut then: F) -> io::Result<usize>
@@ -106,24 +115,26 @@ fn main() {
     let mut stdin = stdin.lock();
     let mut chain = create_chain(&cli);
 
-    //TODO: When chain is not empty (i.e. loaded,) it is okay for the input to be empty. (XXX: Should we *ignore* stdin for this? Empty stdin (CTRL+D on TTY) works. Do we actually need to change this behaviour? I don't think so.) (TODO: Add option to skip reading when loading file, maybe?)
-    buffered_read_all_lines(&mut stdin, |string| {
-        chain.feed(&string.split_whitespace()
-                   .filter(|word| !word.is_empty())
-                   .map(|s| s.to_owned()).collect::<Vec<_>>());
-	
-	Ok(())
-    }).expect("Failed to read from stdin");
+    if !(cli.write_only || (cli.no_consume && ! chain.is_empty())) {
+	buffered_read_all_lines(&mut stdin, |string| {
+            chain.feed(&string.split_whitespace()
+                       .filter(|word| !word.is_empty())
+                       .map(|s| s.to_owned()).collect::<Vec<_>>());
+	    
+	    Ok(())
+	}).expect("Failed to read from stdin");
+    }
 
     if !chain.is_empty() {
-	let lines = cli.lines.map(NonZeroUsize::get).unwrap_or(1);
-	if lines > 1 {
-	    for string in chain.str_iter_for(lines) {
-		println!("{}", string);
-	    }
-	} else {
-	    println!("{}", chain.generate_str());
-	}
+	match cli.lines {
+	    0 => (),
+	    1 =>    println!("{}", chain.generate_str()),
+	    lines => {
+		for string in chain.str_iter_for(lines) {
+		    println!("{}", string);
+		}
+	    },
+	};
     }
 
     complete_chain(&cli, chain).unwrap();