From 78b86b35314b441dd127578235523f1403855a4e Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Wed, 11 Mar 2020 04:19:24 -0700
Subject: [PATCH] WIP stuff about type names

---
 schala-lang/language/src/parser.rs | 100 +++++++++++++++++++++++++++--
 1 file changed, 96 insertions(+), 4 deletions(-)

diff --git a/schala-lang/language/src/parser.rs b/schala-lang/language/src/parser.rs
index 635c1b4..d0b9548 100644
--- a/schala-lang/language/src/parser.rs
+++ b/schala-lang/language/src/parser.rs
@@ -8,7 +8,7 @@ use nom::character::complete::{one_of, space0, alphanumeric0};
 use nom::bytes::complete::{tag, take, take_while, take_while1, take_until};
 use nom::combinator::{cut, cond, map, map_res, value, opt, verify};
 use nom::multi::{separated_list, separated_nonempty_list, many1, many0};
-use nom::error::{context, ParseError, VerboseError};
+use nom::error::{context, ParseError, VerboseError, ErrorKind, make_error};
 use nom::branch::alt;
 use nom::sequence::{pair, tuple, delimited, preceded};
 
@@ -326,11 +326,11 @@ fn expr_or_block(text: &str) -> ParseResult<Block> {
 fn block(text: &str) -> ParseResult<Block> {
   use nom::character::complete::char;
   //TODO fix this so it can handle nested statements
-  delimited(char('{'),
+  delimited(ws(char('{')),
     separated_nonempty_list(statement_sep,
       map(expression, |e| Statement { id: ItemId::new(0), kind: StatementKind::Expression(e) })
     ),
-  char('}'))(text)
+  ws(char('}')))(text)
 }
 
 fn call_expr(text: &str) -> ParseResult<ExpressionKind> {
@@ -411,8 +411,100 @@ fn expression(text: &str) -> ParseResult<Expression> {
   Ok((rest, expr))
 }
 
+fn import(text: &str) -> ParseResult<ImportSpecifier> {
+  let p = preceded(
+    tag("import"),
+    separated_nonempty_list(tag("::"), identifier)
+  );
+  map(p, |path_components| ImportSpecifier {
+    id: ItemId::new(0),
+    path_components,
+    imported_names: ImportedNames::LastOfPath, //TODO finish
+  })(text)
+}
+
+fn module(text: &str) -> ParseResult<ModuleSpecifier> {
+  let p = tuple((tag("module"), ws(identifier), ws(block)));
+  map(p, |(_, name, contents)| ModuleSpecifier { name, contents })
+    (text)
+}
+
+fn declaration(text: &str) -> ParseResult<Declaration> {
+  alt((
+    func_declaration,
+    type_declaration,
+  ))(text)
+}
+
+fn func_declaration(text: &str) -> ParseResult<Declaration> {
+  use Declaration::*;
+  let p = tuple((func_signature, opt(block)));
+  map(p, |(signature, maybe_block)| match maybe_block {
+    Some(block) => FuncDecl(signature, block),
+    None => FuncSig(signature),
+  })(text)
+}
+
+fn func_signature(text: &str) -> ParseResult<Signature> {
+  let p = preceded(tag("fn"), tuple((identifier, formal_params, opt(type_anno))));
+  //TODO fix op
+  map(p, |(name, params, type_anno)| Signature { name, params, type_anno, operator: false })
+    (text)
+}
+
+fn formal_params(text: &str) -> ParseResult<Vec<FormalParam>> {
+  delimited(tag("("), ws(separated_list(ws(tag(",")), formal_param)), tag(")"))(text)
+}
+
+fn formal_param(text: &str) -> ParseResult<FormalParam> {
+  let p = tuple((identifier, opt(type_anno)));
+  //TODO handle default arg
+}
+
+fn type_declaration(text: &str) -> ParseResult<Declaration> {
+  preceded(tag("type"), ws(type_declaration_body))(text)
+}
+
+fn type_declaration_body(text: &str) -> ParseResult<Declaration> {
+  let t = tuple((opt(tag("mut"))), ws(type_singleton_name), ws(tag("=")), ws(type_body));
+  alt((
+    preceded(tag("alias"), ws(type_alias)),
+    map(t, |(mut_kw, name, _, body)| {
+      Declaration::TypeDecl { name, body, mutable: mut_kw.is_some() }
+    })
+  ))(text)
+}
+
+fn type_singleton_name(text: &str) -> ParseResult<TypeSingletonName> {
+  tuple((identifier, opt(delimited(tag("<"),
+    separated_nonempty_list(tag(","), ws(type_name)),
+  tag(">")))))(text)
+}
+
+fn type_alias(text: &str) -> ParseResult<Declaration> {
+  let p = tuple((ws(identifier), ws(tag("=")), ws(identifier)));
+  map(p, |(alias, _, original)| Declaration::TypeAlias { alias, original })
+    (text)
+}
+
+fn statement(text: &str) -> ParseResult<Statement> {
+  let p = alt((
+    map(import, StatementKind::Import),
+    map(module, StatementKind::Module),
+    map(declaration, StatementKind::Declaration),
+    map(expression, StatementKind::Expression),
+  ));
+  map(p, |kind| Statement { id: ItemId::new(0), kind })(text)
+}
+
+pub fn parse_ast(text: &str) -> ParseResult<AST> {
+  map(separated_list(statement_sep, statement),
+  |statements| AST { id: ItemId::new(0), statements }
+  )(text)
+}
+
 pub fn perform_parsing(input: &str) -> Result<String, String> {
-  let output = match expression(input) {
+  let output = match parse_ast(input) {
     Ok((rest, ast)) => format!("{:?} (rest: {})", ast, rest),
     Err(nom::Err::Incomplete(needed)) => format!("Incomplete: {:?}" ,needed),
     Err(nom::Err::Error(verbose_error) | nom::Err::Failure(verbose_error)) => {