Added pretty printing and parquet

Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "csvgr"
+name = "dr"
 version = "0.1.0"
 edition = "2021"
 
@@ -7,5 +7,7 @@ edition = "2021"
 
 [dependencies]
 clap = {version = "4.0", features = ["cargo"]}
-polars = "0.25.1"
+polars = "0.25"
 polars-sql = "0.2.1"
+polars-lazy = "0.25"
+polars-io = {"version" = "0.25", features = ["parquet"]}

src/io.rs

@@ -0,0 +1,45 @@
+use polars::frame::DataFrame;
+use polars::prelude::*;
+use std::io;
+use std::io::Read;
+
+/// Read CSV format from stdin and return a Polars DataFrame
+pub fn load_csv_from_stdin() -> DataFrame {
+    let mut buffer = String::new();
+    let _res: () = match io::stdin().read_to_string(&mut buffer) {
+        Ok(_ok) => (),
+        Err(_e) => (),
+    };
+    let cursor = io::Cursor::new(buffer.as_bytes());
+    let df = match CsvReader::new(cursor).finish() {
+        Ok(df) => df,
+        Err(_e) => DataFrame::default(),
+    };
+    df
+}
+
+/// Take a Polars Dataframe and write it as CSV to stdout
+pub fn dump_csv_to_stdout(df: &mut DataFrame) {
+    let _res: () = match CsvWriter::new(io::stdout().lock()).finish(df) {
+        Ok(_ok) => (),
+        Err(_e) => (),
+    };
+}
+
+/// Read parquet format from stdin and return a Polars DataFrame
+pub fn load_parquet_from_stdin() -> DataFrame {
+    let mut buffer: String = String::new();
+    let _res: () = match io::stdin().read_to_string(&mut buffer) {
+        Ok(_ok) => (),
+        Err(_e) => (),
+    };
+    let cursor = io::Cursor::new(buffer.as_bytes());
+    let df = match ParquetReader::new(cursor).finish() {
+        Ok(df) => df,
+        Err(e) => {
+            eprintln!("{e}");
+            DataFrame::default()
+        }
+    };
+    df
+}

src/main.rs

@@ -1,6 +1,6 @@
+mod io;
 mod sql;
 use clap::{arg, command, Command};
-use polars::prelude::*;
 
 fn main() {
     let matches = command!()
@@ -10,25 +10,31 @@ fn main() {
                 .arg(arg!([statement] "SQL statement"))
                 .arg(arg!(-d --delimiter <String> "Column delimiter").required(false)),
         )
+        .subcommand(Command::new("print").about("Pretty prints the table"))
+        .subcommand(Command::new("rpq").about("Read parquet file"))
         .get_matches();
 
     if let Some(matches) = matches.subcommand_matches("sql") {
-        if let Some(delimiter) = matches.get_one::<String>("delimiter") {
-            println!("Delimiter: {delimiter}")
-        } else {
-            println!("No delimiter")
-        }
+        //if let Some(delimiter) = matches.get_one::<String>("delimiter") {
+        //    println!("DEBUG: Delimiter: {delimiter}")
+        //} else {
+        //    println!("DEBUG: No delimiter")
+        //}
         if let Some(statement) = matches.get_one::<String>("statement") {
-            println!("Statement: {statement}");
+            sql::execute(statement);
         } else {
-            let mut df = match sql::load_csv_from_stdin() {
-                Ok(df) => df,
-                Err(_e) => DataFrame::default(),
-            };
-            let _res = match sql::dump_csv_to_stdout(&mut df) {
-                Ok(_df) => (),
-                Err(_e) => (),
-            };
+            let mut df = io::load_csv_from_stdin();
+            io::dump_csv_to_stdout(&mut df);
         }
     }
+
+    if let Some(_matches) = matches.subcommand_matches("print") {
+        let df = io::load_csv_from_stdin();
+        println!("{}", df)
+    }
+
+    if let Some(_matches) = matches.subcommand_matches("rpq") {
+        let mut df = io::load_parquet_from_stdin();
+        io::dump_csv_to_stdout(&mut df);
+    }
 }

src/sql.rs

@@ -1,17 +1,19 @@
-use polars::frame::DataFrame;
-use polars::prelude::*;
-use std::io;
-use std::io::Read;
+use crate::io::dump_csv_to_stdout;
+use crate::io::load_csv_from_stdin;
+use polars_lazy::frame::IntoLazy;
+use polars_sql::SQLContext;
 
-/// Read from stdin from CSV format and return a Polars DataFrame
-pub fn load_csv_from_stdin() -> PolarsResult<DataFrame> {
-    let mut buffer = String::new();
-    io::stdin().read_to_string(&mut buffer)?;
-    let cursor = io::Cursor::new(buffer.as_bytes());
-    CsvReader::new(cursor).finish()
-}
-
-/// Take a Polars Dataframe and write it as CSV to stdout
-pub fn dump_csv_to_stdout(df: &mut DataFrame) -> Result<(), PolarsError> {
-    CsvWriter::new(io::stdout().lock()).finish(df)
+pub fn execute(statement: &String) {
+    if let Ok(mut context) = SQLContext::try_new() {
+        let df = load_csv_from_stdin();
+        context.register("this", df.lazy());
+        if let Ok(res) = context.execute(statement) {
+            if let Ok(mut res) = res.collect() {
+                dump_csv_to_stdout(&mut res);
+            };
+        };
+        if let Err(e) = context.execute(statement) {
+            eprintln!("Query execution error {e}")
+        };
+    };
 }