renamed config-parser and implemented the first set of functions for the

macro
extended and cleaned up format.rs and moved it into `config-parser`
some other bits and bobs

config-parser/config-parser-macro/src/lib.rs

@@ -0,0 +1,100 @@
+use config_parser_common::common::gen_config_load_function;
+use proc_macro2::TokenStream;
+use syn::{parse_macro_input, DeriveInput};
+use quote::quote;
+
+/// **for structs only**
+/// - implements `parse_config(&mut self, input: &String) -> Result<()>`
+/// which parses a string and fills the fills recognised values into the struct
+/// - implements `write_default_config() -> Result<String>`
+/// which write a default configuration, in case the documentation is lacking
+#[proc_macro_derive(ConfigParser, attributes(color_config, nested_config, no_config))]
+pub fn derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let ast = parse_macro_input!(input as DeriveInput);
+    let name = &ast.ident;
+    let config_name = syn::Ident::new("config", name.span()); // TODO: use correct span
+    let fields = if let syn::Data::Struct(syn::DataStruct{ fields: syn::Fields::Named(syn::FieldsNamed{ ref named, .. }), .. }) = ast.data {
+        named
+    } else {
+        panic!("the macro `ConfigParser` applies only to structs!");
+    };
+    let assignments = match gen_config_load_function(fields, &config_name) {
+        Ok(value) => value,
+        Err(_) => panic!("loading config failed"),
+    };
+
+    if name.to_string() == "Settings" {
+        let string = format!("{:#?}", ast);
+        _ = std::fs::write("test.txt", string);
+    }
+
+    let expanded_stream: TokenStream = quote! {
+        impl #name {
+            /// tries to parse config from a string
+            pub fn parse_from_string(&mut self, input: &String) -> std::io::Result<()> {
+                let mut #config_name : std::collections::HashMap<String, String> = Self::parse_config_file(input)?;
+
+                #assignments
+
+                if !#config_name.is_empty() {
+                    let leftovers = #config_name.keys().cloned().collect::<Vec<String>>();
+                    return Err(std::io::Error::other(format!("the following settings were not recognised: {:#?}", leftovers)));
+                }
+                Ok(())
+            }
+
+            /// **do not call**
+            /// this function needs to be public for nested configs but is not intended
+            /// to be called by the user
+            pub fn parse_from_map(&mut self, input: &mut std::collections::HashMap<String, String>) -> std::io::Result<()> {
+                let mut #config_name = input;
+
+                #assignments
+
+                Ok(())
+            }
+
+            fn parse_config_file(input: &String) -> std::io::Result<std::collections::HashMap<String, String>> {
+                let mut config = std::collections::HashMap::<String, String>::new();
+                let lines = input.lines();
+
+                for line in lines {
+                    let mut line = line.trim();
+                    // ignore empty lines
+                    if line.is_empty() { continue; }
+
+                    if line.starts_with("[") {
+                        // check for table
+                        if !line.ends_with("]") {
+                            // TODO: implement error handling
+                        } else if line.contains(' ') {
+                            // TODO: implement error handling
+                        }
+                        //let tokens = line.split('.');
+                        // TODO: implement hirarchical map
+                    } else {
+                        // check for config
+                        let mut tokens: Vec<&str> = line.split('=').map(|entry| entry.trim()).collect();
+                        tokens.retain(|entry| !entry.is_empty());
+                        if tokens.len() != 2 {
+                            // println!("error in line'", line);
+                            continue;
+                        }
+                        config.insert(tokens[0].to_string(), tokens[1].to_string());
+                    }
+
+                }
+                Ok(config)
+            }
+
+            // TODO: implement
+            pub fn write_default_config(&self) -> Result<()> {
+                Ok(())
+            }
+
+            // TODO: implement function to parse style settings
+        }
+    }.into();
+    expanded_stream.into()
+}
+