Add option to specify delimiter including escaped.

Author: ahcm

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "hist-cli"
-version = "0.4.4"
+version = "0.4.5"
 edition = "2021"
 authors = ["Andreas Hauser <Andreas.Hauser@LMU.de>"]
 description = "Commandline tool for plotting frequency ranked histograms of TSV/CSV data"

README.md

@@ -10,7 +10,7 @@ export PATH="$HOME/.cargo/bin:$PATH"
 
 ## Usage
 ```
-hist 0.4.4
+hist 0.4.5
 Plots histogram of input
 
 USAGE:
@@ -23,13 +23,14 @@ FLAGS:
     -V, --version     Prints version information
 
 OPTIONS:
-    -T, --Title <Title>          optional title above the plot [default: Counts distribution]
-    -g, --geometry <geometry>    the x and y size of the plot [default: 1280x960]
-    -k, --key <key>              key (column) selector [default: 1]
-    -o, --output <output>        file to save PNG plot to [default: histogram.png]
-    -s, --save <save>            save counts data to file as TSV, use - for STDOUT
-        --xdesc <xdesc>          x-axis label [default: Rank]
-        --ydesc <ydesc>          y-axis label [default: Counts]
+    -T, --Title <Title>            optional title above the plot [default: Counts distribution]
+    -d, --delimiter <delimiter>    column delimiter [default: \t]
+    -g, --geometry <geometry>      the x and y size of the plot [default: 1280x960]
+    -k, --key <key>                key (column) selector [default: 1]
+    -o, --output <output>          file to save PNG plot to [default: histogram.png]
+    -s, --save <save>              save counts data to file as TSV, use - for STDOUT
+        --xdesc <xdesc>            x-axis label [default: Rank]
+        --ydesc <ydesc>            y-axis label [default: Counts]
 
 ARGS:
     <input>    optional file with on entry per line [default: STDIN]

src/bin/hist.rs

@@ -18,6 +18,11 @@ struct Opt
     /// optional file with on entry per line [default: STDIN]
     input: Option<PathBuf>,
 
+    // r"" makes it prinable as escaped in default
+    #[structopt(short, long, default_value = r"\t")]
+    /// column delimiter
+    delimiter: String,
+
     #[structopt(long, short, default_value = "1")]
     /// key (column) selector
     key: usize,
@@ -69,9 +74,17 @@ fn main() -> Result<(), Box<dyn Error>>
             Box::new(io::stdin())
         };
 
+    // accept escaped delimiters
+    // could be expanded to aliases e.g. "TAB"
+    let delimiter = match opt.delimiter.as_str()
+    {
+        r"\t" => b'\t', // structopt needs r"" to show default as escaped, also for sepcifiying as escaped in CLI
+         _ => *opt.delimiter.as_bytes().first().expect("Not a valid delimiter")
+    };
+
     let mut reader = csv::ReaderBuilder::new()
         .has_headers(false)
-        .delimiter(b'\t')
+        .delimiter(delimiter)
         .from_reader(input);
 
     let mut key_counts = BTreeMap::new();