neoh 0.1.5

A declarative HDL transpiler for rapid testbench development.
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/*
 * Copyright 2026 stefand-0
 * Licensed under the Apache License, Version 2.0 (the "License");
 */

use crate::ast::*;

pub struct Emitter { pub output: String }

impl Emitter {
    pub fn new() -> Self { Self { output: String::new() } }
    
    pub fn emit_file(&mut self, file: &File) {
        self.output.push_str("`timescale 1ns / 1ps\n\n");
        for stmt in &file.statements {
            match stmt {
                Statement::Block(b) => self.emit_block(b),
                Statement::Testbench(t) => self.emit_testbench(t),
                Statement::Testgroup(g) => self.emit_testgroup(g),
                Statement::Piece(p) => self.emit_piece(p),
                Statement::Known(_, _) => {},
            }
        }
    }

    fn emit_block(&mut self, b: &BlockDef) {
        self.output.push_str(&format!("module {}();\n", b.name));
        for stmt in &b.body {
            match stmt {
                BlockStmt::RetAssign(r) => {
                    let w = r.width.as_ref().map(|x| format!("[{}:{}]", x.msb, x.lsb)).unwrap_or_default();
                    self.output.push_str(&format!("  assign {} {} = {};\n", w, r.target, r.expr));
                }
                BlockStmt::PassParams(p) => {
                    self.output.push_str(&format!("  {} {}({});\n", p.block_type, p.inst_name, p.params.join(", ")));
                }
                _ => {}
            }
        }
        self.output.push_str("endmodule\n");
    }

    fn emit_testbench(&mut self, t: &TestbenchDef) {
        self.output.push_str(&format!("module tb_{}();\n", t.name));
        self.output.push_str(&format!("  {} dut();\n", t.target));
        self.output.push_str("  initial begin\n");
        for cmd in &t.body {
            self.emit_verif_cmd(cmd);
        }
        self.output.push_str("  end\nendmodule\n");
    }

    fn emit_verif_cmd(&mut self, cmd: &VerifCmd) {
        match cmd {
            VerifCmd::Expect { time, lhs, rhs } => 
                self.output.push_str(&format!("    #{} assert({} == {});\n", time, lhs, rhs)),
            VerifCmd::Pulse { len, gap } => 
                self.output.push_str(&format!("    {} = 1; #{} {} = 0; #{} {} = 0;\n", len, len, len, gap, gap)),
            VerifCmd::Watchfor { lhs, rhs, time_b, out, .. } => {
                let out_sv = match out { OutTarget::Variable(v) => v.clone(), OutTarget::Literal(s) => s.clone() };
                self.output.push_str(&format!("    wait({} == {}); #{} ({});\n", lhs, rhs, time_b, out_sv));
            }
            VerifCmd::Write(w) => self.output.push_str(&format!("    {} = {};\n", w.target, w.val)),
            VerifCmd::Put(p) => self.emit_put(p),
            // Added support for your new grammar rules
            VerifCmd::Out { time, target } => {
                let t_str = match target { OutTarget::Variable(v) => v.clone(), OutTarget::Literal(s) => s.clone() };
                self.output.push_str(&format!("    #{} $display({});\n", time, t_str));
            },
            VerifCmd::WriteFile { file, .. } => {
                self.output.push_str(&format!("    $dumpfile(\"{}\"); $dumpvars;\n", file));
            }
        }
    }

    fn emit_put(&mut self, p: &PutStmt) {
        self.output.push_str(&format!("    {} {} {};\n", p.target, p.op, p.expr));
    }

    fn emit_testgroup(&mut self, g: &TestGroupDef) {
        self.output.push_str(&format!("module tg_{}();\n", g.name));
        // Testgroup logic remains standard
        self.output.push_str("endmodule\n");
    }

    fn emit_piece(&mut self, _p: &PieceDef) { /* Handle interface definition */ }
}