From 49240a80ad9ae20d842c0e2a3fa5d9a219eb3670 Mon Sep 17 00:00:00 2001
From: ychenfo <yc@m-labs.hk>
Date: Wed, 24 Nov 2021 18:24:16 +0800
Subject: [PATCH] nac3standalone: iteration over multiple typevar assignment in
 the same line

---
 nac3core/src/toplevel/mod.rs |  2 +-
 nac3standalone/src/main.rs   | 97 ++++++++++++++++++++++++++++++++----
 2 files changed, 89 insertions(+), 10 deletions(-)

diff --git a/nac3core/src/toplevel/mod.rs b/nac3core/src/toplevel/mod.rs
index f6fc15b..bcf1e62 100644
--- a/nac3core/src/toplevel/mod.rs
+++ b/nac3core/src/toplevel/mod.rs
@@ -24,7 +24,7 @@ pub struct DefinitionId(pub usize);
 
 pub mod composer;
 pub mod helper;
-mod type_annotation;
+pub mod type_annotation;
 use composer::*;
 use type_annotation::*;
 #[cfg(test)]
diff --git a/nac3standalone/src/main.rs b/nac3standalone/src/main.rs
index f6c4be6..55c66d9 100644
--- a/nac3standalone/src/main.rs
+++ b/nac3standalone/src/main.rs
@@ -3,8 +3,9 @@ use inkwell::{
     targets::*,
     OptimizationLevel,
 };
-use nac3core::typecheck::type_inferencer::PrimitiveStore;
+use nac3core::typecheck::{type_inferencer::PrimitiveStore, typedef::{Type, Unifier}};
 use nac3parser::{ast::{Expr, ExprKind, StmtKind}, parser};
+use parking_lot::RwLock;
 use std::{borrow::Borrow, env};
 use std::fs;
 use std::{collections::HashMap, path::Path, sync::Arc, time::SystemTime};
@@ -15,7 +16,11 @@ use nac3core::{
         WorkerRegistry,
     },
     symbol_resolver::SymbolResolver,
-    toplevel::{composer::TopLevelComposer, TopLevelDef, helper::parse_parameter_default_value},
+    toplevel::{
+        composer::TopLevelComposer,
+        TopLevelDef, helper::parse_parameter_default_value,
+        type_annotation::*,
+    },
     typecheck::typedef::FunSignature,
 };
 
@@ -68,25 +73,84 @@ fn main() {
 
     for stmt in parser_result.into_iter() {
         if let StmtKind::Assign { targets, value, .. } = &stmt.node {
+            fn handle_typevar_definition(
+                var: &Expr,
+                resolver: &(dyn SymbolResolver + Send + Sync),
+                def_list: &[Arc<RwLock<TopLevelDef>>],
+                unifier: &mut Unifier,
+                primitives: &PrimitiveStore,
+            ) -> Result<Type, String> {
+                if let ExprKind::Call { func, args, .. } = &var.node {
+                    if matches!(&func.node, ExprKind::Name { id, .. } if id == &"TypeVar".into()) {
+                        let constraints = args
+                            .iter()
+                            .skip(1)
+                            .map(|x| -> Result<Type, String> {
+                                let ty = parse_ast_to_type_annotation_kinds(
+                                    resolver,
+                                    def_list,
+                                    unifier,
+                                    primitives,
+                                    x,
+                                    Default::default(),
+                                )?;
+                                get_type_from_type_annotation_kinds(def_list, unifier, primitives, &ty)
+                            })
+                            .collect::<Result<Vec<_>, _>>()?;
+                        Ok(unifier.get_fresh_var_with_range(&constraints).0)
+                    } else {
+                        Err(format!("expression {:?} cannot be handled as a TypeVar in global scope", var))
+                    }
+                } else {
+                    Err(format!("expression {:?} cannot be handled as a TypeVar in global scope", var))
+                }
+            }
+
             fn handle_assignment_pattern(
                 targets: &[Expr],
                 value: &Expr,
                 resolver: &(dyn SymbolResolver + Send + Sync),
                 internal_resolver: &ResolverInternal,
+                def_list: &[Arc<RwLock<TopLevelDef>>],
+                unifier: &mut Unifier,
+                primitives: &PrimitiveStore,
             ) -> Result<(), String> {
                 if targets.len() == 1 {
                     match &targets[0].node {
                         ExprKind::Name { id, .. } => {
-                            let val = parse_parameter_default_value(value.borrow(), resolver)?;
-                            internal_resolver.add_module_global(*id, val);
-                            Ok(())
+                            if let Ok(var) = handle_typevar_definition(
+                                value.borrow(),
+                                resolver,
+                                def_list,
+                                unifier,
+                                primitives,
+                            ) {
+                                internal_resolver.add_id_type(*id, var);
+                                Ok(())
+                            } else if let Ok(val) = parse_parameter_default_value(value.borrow(), resolver) {
+                                internal_resolver.add_module_global(*id, val);
+                                Ok(())
+                            } else {
+                                Err(format!("fails to evaluate this expression `{:?}` as a constant or TypeVar at {}",
+                                    targets[0].node,
+                                    targets[0].location,
+                                ))
+                            }
                         }
                         ExprKind::List { elts, .. }
                         | ExprKind::Tuple { elts, .. } => {
-                            handle_assignment_pattern(elts, value, resolver, internal_resolver)?;
+                            handle_assignment_pattern(
+                                elts,
+                                value,
+                                resolver,
+                                internal_resolver,
+                                def_list,
+                                unifier,
+                                primitives
+                            )?;
                             Ok(())
                         }
-                        _ => unreachable!("cannot be assigned")
+                        _ => Err(format!("assignment to {:?} is not supported at {}", targets[0], targets[0].location))
                     }
                 } else {
                     match &value.node {
@@ -105,7 +169,10 @@ fn main() {
                                         std::slice::from_ref(tar),
                                         val,
                                         resolver,
-                                        internal_resolver
+                                        internal_resolver,
+                                        def_list,
+                                        unifier,
+                                        primitives
                                     )?;
                                 }
                                 Ok(())
@@ -115,7 +182,19 @@ fn main() {
                     }
                 }
             }
-            if let Err(err) = handle_assignment_pattern(targets, value, resolver.as_ref(), internal_resolver.as_ref()) {
+
+            let def_list = composer.extract_def_list();
+            let unifier = &mut composer.unifier;
+            let primitives = &composer.primitives_ty;
+            if let Err(err) = handle_assignment_pattern(
+                targets,
+                value,
+                resolver.as_ref(),
+                internal_resolver.as_ref(),
+                &def_list,
+                unifier,
+                primitives,
+            ) {
                 eprintln!("{}", err);
                 return;
             }