Initial treesap implementation

Author: morr0ne

Cargo.lock

@@ -23,3 +23,8 @@ lto = true
 codegen-units = 1
 strip = true
 panic = "abort"
+
+[dev-dependencies]
+anyhow = "1.0.100"
+bitflags = "2.10.0"
+itoa = "1.0.15"

Cargo.toml

@@ -3,4 +3,14 @@ name = "treesap"
 version = "0.1.0"
 edition = "2024"
 
+[lib]
+proc-macro = true
+
 [dependencies]
+darling = "0.21.3"
+quote = "1.0.41"
+syn = { version = "2.0.108", features = ["full"] }
+
+[dev-dependencies]
+anyhow = "1.0.100"
+sap = { path = ".." }

treesap/Cargo.toml

@@ -0,0 +1,16 @@
+use anyhow::Result;
+use treesap::Parser;
+
+#[derive(Debug, Parser)]
+struct Args {
+    #[arg(short, long)]
+    verbose: bool,
+}
+
+fn main() -> Result<()> {
+    let args = Args::parse()?;
+
+    dbg!(args);
+
+    Ok(())
+}

treesap/examples/derive.rs

@@ -1 +1,81 @@
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{Data, DataStruct, DeriveInput, parse_macro_input};
 
+#[proc_macro_derive(Parser, attributes(arg, command))]
+pub fn derive_parser(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    let ident = input.ident;
+
+    match input.data {
+        Data::Struct(DataStruct { fields, .. }) => {
+            let mut field_declarations = Vec::new();
+            let mut field_setters = Vec::new();
+            let mut field_getters = Vec::new();
+
+            for field in fields {
+                let ident = field.ident.unwrap();
+                let ty = field.ty;
+                let option = ident.to_string();
+
+                field_declarations.push(quote! {
+                    let mut #ident: Option<#ty> = None;
+                });
+
+                field_setters.push(quote! {
+                    sap::Argument::Long(#option) => { #ident = Some(true) }
+                });
+
+                field_getters.push(quote! {
+                    #ident: #ident.unwrap()
+                });
+            }
+
+            quote! {
+                impl #ident {
+                    const HELP: &str = "";
+
+                    pub fn parse() -> ::sap::Result<Self> {
+                        use std::io::Write as _;
+
+                        let mut arg_parser = sap::Parser::from_env()?;
+
+                        #(#field_declarations)*
+
+                        while let Some(arg) = arg_parser.forward()? {
+
+                            match arg {
+                                // Long("version") => {
+                                //     stdout
+                                //         .write_all(
+                                //             "wc (puppyutils) 0.0.1\nLicensed under the European Union Public Licence (EUPL) <https://eupl.eu/>\n"
+                                //                 .as_bytes(),
+                                //         )?;
+                                //     stdout.flush()?;
+                                //     std::process::exit(0);
+                                // }
+                                // Long("help") => {
+                                //     stdout
+                                //         .write_all(
+                                //             "Usage: wc [OPTION]... [FILE]...\nPrint newline, word, and byte counts for each FILE.  A word is a nonempty \nsequence of non white space delimited by white space characters or by start \nor end of input.\n\n  -c, --bytes    print the byte counts\n  -m, --chars    print the character counts\n  -l, --lines    print the newline counts\n  -w, --words    print the word counts\n      --help     display this help and exit\n      --version  output version information and exit\n\nWith no FILE, or when FILE is -, read standard input.\n"
+                                //                 .as_bytes(),
+                                //         )?;
+                                //     stdout.flush()?;
+                                //     std::process::exit(0);
+                                // }
+                                #(#field_setters),*
+                                arg => return Err(arg.into_error(None)),
+                            }
+                        }
+
+                        Ok(Self { #(#field_getters),* })
+                    }
+                }
+
+            }
+            .into()
+        }
+        Data::Enum(_data_enum) => todo!(),
+        Data::Union(_data_union) => todo!(),
+    }
+}