Support Passing Python Variable for Module

Cargo.toml

@@ -3,7 +3,7 @@ name = "pytv"
 description = "Python Templated Verilog"
 repository = "https://github.com/autohdw/pytv"
 authors = ["Teddy van Jerry <me@teddy-van-jerry.org>"]
-version = "0.4.0"
+version = "0.5.0"
 readme = "README.md"
 license = "GPL-3.0-or-later"
 keywords = ["verilog", "python", "template", "generation"]

examples/D1.pytv

@@ -1,6 +1,6 @@
 //! # port enable settings
-//! if_rst = True
-//! if_en  = True
+//! # parameter: if_rst = True
+//! # parameter: if_en  = True
 // Delay by 1 clock
 `timescale 1ns / 1ps
 

src/config.rs

@@ -1,5 +1,6 @@
 use clap::Parser;
 use regex::Regex;
+use std::error::Error;
 
 /// Represents the configuration options for PyTV.
 #[derive(Debug)]
@@ -38,6 +39,15 @@ impl Default for Config {
     }
 }
 
+/// Parse a single key-value pair
+fn parse_key_val(s: &str) -> Result<(String, String), Box<dyn Error>>
+{
+    let pos = s
+        .find('=')
+        .ok_or_else(|| format!("invalid KEY=value: no `=` found in `{}`", s))?;
+    Ok((s[..pos].to_string(), s[pos + 1..].to_string()))
+}
+
 /// Python Templated Verilog
 #[derive(Parser, Debug)]
 #[command(version, about, long_about = None)]
@@ -70,6 +80,9 @@ struct Args {
     /// Magic comment string (after "//")
     #[arg(short, long, default_value = "!", value_name = "STRING")]
     magic: String,
+    /// Variables (multiple occurrences allowed)
+    #[arg(short, long = "var", value_name = "KEY=VAL")]
+    vars: Vec<String>,
 }
 
 impl Config {
@@ -100,8 +113,17 @@ impl Config {
     }
 
     /// Parses the command line arguments and returns a tuple of `Config` and `FileOptions`.
-    pub fn from_args() -> (Config, FileOptions) {
+    pub fn from_args() -> (Config, FileOptions, Option<Vec<(String, String)>>) {
         let args = Args::parse();
+        let vars = args
+            .vars
+            .iter()
+            .map(|s| parse_key_val(s))
+            .collect::<Result<Vec<(String, String)>, Box<dyn Error>>>();
+        if vars.is_err() {
+            eprintln!("Error: {}", vars.err().unwrap());
+            std::process::exit(1);
+        }
         (
             Self::new(
                 args.magic,
@@ -114,6 +136,7 @@ impl Config {
                 input: args.input,
                 output: args.output,
             },
+            vars.ok(),
         )
     }
 

src/convert.rs

@@ -13,6 +13,7 @@ use std::result::Result;
 pub struct Convert {
     config: Config,
     file_options: FileOptions,
+    vars: Option<Vec<(String, String)>>,
 }
 
 #[derive(Debug, PartialEq)]
@@ -31,17 +32,18 @@ impl Default for LineType {
 
 impl Convert {
     /// Creates a new `Convert` instance with the given configuration and file options.
-    pub fn new(config: Config, file_options: FileOptions) -> Convert {
+    pub fn new(config: Config, file_options: FileOptions, vars: Option<Vec<(String, String)>>) -> Convert {
         Convert {
             config,
             file_options,
+            vars,
         }
     }
 
     /// Creates a new `Convert` instance by parsing command line arguments.
     pub fn from_args() -> Convert {
-        let (config, file_options) = Config::from_args();
-        Convert::new(config, file_options)
+        let (config, file_options, vars) = Config::from_args();
+        Convert::new(config, file_options, vars)
     }
 
     /// Opens the input file and reads its contents as a string.
@@ -242,6 +244,12 @@ impl Convert {
         let mut within_inst = false;
         let mut inst_str = String::new();
         #[cfg(feature = "inst")]
+        // print user-defined variables
+        if let Some(vars) = &self.vars {
+            for (name, value) in vars {
+                writeln!(stream, "{} = {}", name, value)?;
+            }
+        }
         writeln!(
             stream,
             concat!(