Remove cruft from ungram, SyntaxKind, etc. (#96)

Removed unused symbols, variants, constructs.
Use better names in some cases.

crates/oq3_parser/src/grammar.rs

@@ -94,28 +94,27 @@ impl BlockLike {
     }
 }
 
-fn plain_type(p: &mut Parser<'_>) {
-    assert!(p.current().is_type_name());
+fn scalar_type(p: &mut Parser<'_>) {
+    assert!(p.current().is_scalar_type());
     let r = p.start();
     p.bump_any();
-    r.complete(p, PATH_TYPE);
+    r.complete(p, SCALAR_TYPE);
 }
 
-/// Parse the optional return type of a `defcal` or `def` definition.
+/// Parse the optional return signature of a `defcal` or `def` definition.
 /// Return `true` if the return type was found, else `false.
 fn opt_ret_type(p: &mut Parser<'_>) -> bool {
     if p.at(T![->]) {
         let m = p.start();
         p.bump(T![->]);
-        //        types::type_no_bounds(p);
         if p.current().is_type_name() {
-            plain_type(p);
+            scalar_type(p);
         } else {
             p.error("Expected return type after ->");
             m.abandon(p);
             return false;
         }
-        m.complete(p, RET_TYPE);
+        m.complete(p, RETURN_SIGNATURE);
         true
     } else {
         false

crates/oq3_parser/src/syntax_kind/syntax_kind_enum.rs

@@ -141,28 +141,20 @@ pub enum SyntaxKind {
     BARRIER,
     DEF,
     RESET,
-    RET_TYPE,
     CONST,
-    PAREN_TYPE,
-    PATH_TYPE,
-    SLICE_TYPE,
     TUPLE_EXPR,
     ARRAY_EXPR,
     PAREN_EXPR,
-    PATH_EXPR,
     IF_STMT,
     WHILE_STMT,
     FOR_STMT,
     END_STMT,
     CONTINUE_STMT,
     BREAK_STMT,
-    LABEL,
     BLOCK_EXPR,
     STMT_LIST,
     RETURN_EXPR,
     LET_STMT,
-    ALIAS_EXPR,
-    CONCATENATION_EXPR,
     BOX_EXPR,
     CALL_EXPR,
     GATE_CALL_EXPR,
@@ -173,41 +165,27 @@ pub enum SyntaxKind {
     PREFIX_EXPR,
     RANGE_EXPR,
     BIN_EXPR,
-    SET_NUM,
-    EXTERN_ITEM,
-    ITEM_LIST,
-    PATH,
-    PATH_SEGMENT,
     LITERAL,
     NAME,
     EXPR_STMT,
     TYPE_SPEC,
     TYPE,
-    NEW_TYPE,
-    DECLARED_VAR,
     TYPE_DECLARATION_STMT,
-    RETURN_TYPE_ARG,
-    CONST_PARAM,
-    CONST_ARG,
     PARAM_LIST,
     QUBIT_LIST,
     FILE_PATH,
     PARAM,
     ARG_LIST,
-    GATE_ARG_LIST,
     VERSION,
     VERSION_STRING,
     INCLUDE,
     DECLARATION,
     DESIGNATOR,
     SCALAR_TYPE,
-    SCALAR_TYPE_NAME,
     ARRAY_TYPE,
     QUBIT_TYPE,
     EXPRESSION_LIST,
     RETURN_SIGNATURE,
-    INT_NUM,
-    ALIAS_EXPRESSION,
     SET_EXPRESSION,
     ALIAS_DECLARATION_STATEMENT,
     INDEX_OPERATOR,
@@ -218,8 +196,6 @@ pub enum SyntaxKind {
     HARDWARE_QUBIT,
     CLASSICAL_DECLARATION_STATEMENT,
     ASSIGNMENT_STMT,
-    DECLARATION_EXPRESSION,
-    CONST_DECLARATION_STATEMENT,
     I_O_DECLARATION_STATEMENT,
     GATE_OPERAND,
     MEASURE_EXPRESSION,

crates/oq3_semantics/src/asg.rs

@@ -508,14 +508,6 @@ impl Default for Block {
     }
 }
 
-// #[test]
-// fn test_construct_block() {
-//     let mut block = Block::new();
-//     let id = make_ident_expr("x", false);
-//     let assign = Stmt::Assignment(Assignment { name: id, rhs: make_int_lit_expr(1) });
-//     block.insert_stmt(assign);
-// }
-
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct GateDeclaration {
     name: SymbolIdResult,

crates/oq3_syntax/examples/itemparse.rs

@@ -171,8 +171,8 @@ fn print_defcal(defcal: ast::DefCal) {
         println!("parameters: '{}'", defcal.param_list().unwrap());
     }
     println!("qubits: '{}'", defcal.qubit_list().unwrap());
-    if defcal.ret_type().is_some() {
-        println!("return type: '{}'", defcal.ret_type().unwrap());
+    if defcal.return_signature().is_some() {
+        println!("return type: '{}'", defcal.return_signature().unwrap());
     }
     print!("body: '{}'", defcal.body().unwrap());
 }
@@ -182,8 +182,8 @@ fn print_def(def: ast::Def) {
     if def.param_list().is_some() {
         println!("parameters: '{}'", def.param_list().unwrap());
     }
-    if def.ret_type().is_some() {
-        println!("return type: '{}'", def.ret_type().unwrap());
+    if def.return_signature().is_some() {
+        println!("return type: '{}'", def.return_signature().unwrap());
     }
     print!("body: '{}'", def.body().unwrap());
 }

crates/oq3_syntax/openqasm3.ungram

@@ -1,4 +1,4 @@
-// This grammar specifies the structure of Rust's concrete syntax tree.
+// This grammar specifies the structure of the OpenQASM 3 concrete syntax tree.
 // It does not specify parsing rules (ambiguities, precedence, etc are out of scope).
 // Tokens are processed -- contextual keywords are recognised, compound operators glued.
 //
@@ -79,6 +79,7 @@ Item =
 | GPhaseCallStmt
 | LetStmt
 | AssignmentStmt
+| AliasDeclarationStatement
 | Include
 | ForStmt
 | IfStmt
@@ -142,12 +143,12 @@ TypeSpec =
 
 // Subroutine definition
 Def =
- 'def' Name ParamList RetType?
+ 'def' Name ParamList ReturnSignature?
  (body:BlockExpr | ';')
 
 // Defcal definition
 DefCal =
- 'defcal' Name ParamList QubitList RetType?
+ 'defcal' Name ParamList QubitList ReturnSignature?
  (body:BlockExpr | ';')
 
 // Gate definition
@@ -174,10 +175,6 @@ QubitList =
 Param =
    Name
 
-// extern is much different in oq3 than rust
-// This is a placeholder
-ExternItem =
-    Name
 
 //****************************//
 // Statements and Expressions //
@@ -229,16 +226,6 @@ Literal =
 LetStmt =
   'let' Name '=' Expr ';'
 
-// FIXME: Only this binary op is turned into a nary-ish op.
-// Perhaps this should be removed. Possible issues:
-// - Binding power is not expressed here.
-// - If this were repeated it might add more boiler plate. Compare BinExpr below.
-// So an op that might be considered nary is instead parsed as nested binary ops.
-// I recall that Julia's parser changed between nested bin and nary for some ops, perhaps even went back and forth
-// a couple times.
-ConcatenationExpr =
-   Expr '++' Expr concat:('++' Expr)*
-
 BlockExpr =
   '{'
     statements:Stmt*
@@ -375,18 +362,10 @@ ExpressionList =
 ReturnSignature =
   '->' ScalarType
 
-RetType =
-  '->' ScalarType
-
 // Primitive declaration statements.
 
 AliasDeclarationStatement =
-    'let' Name '=' AliasExpression ';'
-
-// label 'concat' is to work around what is probably a bug
-// Parsing this ungram fails with no good diagnostic without it.
-AliasExpression =
-   Expr concat:('++' Expr)*
+    'let' Name '=' Expr ';'
 
 MeasureExpression =
     'measure' GateOperand
@@ -420,11 +399,6 @@ HardwareQubit =
 ClassicalDeclarationStatement =
  'const'? (ScalarType | ArrayType) Name ('=' Expr)? ';'
 
-// We can just use ClassicalDeclarationStatement above.
-// Or split these into {Scalar,Array}DeclarationStatement, where former includes `const`.
-ConstDeclarationStatement =
-    'const' ScalarType Name '=' Expr ';'
-
 IODeclarationStatement =
     ('input' | 'output') (ScalarType | ArrayType) Name ';'