Beginnings of loops

dee-mode.el

@@ -2,12 +2,6 @@
 
 (add-to-list 'auto-mode-alist '("\\.dee\\'" . dee-mode))
 
-(defface dee-function-param-face
-  '((t . (:slant italic
-	  :weight bold
-	  :foreground "orange")))
-  "A face to help identify function parameter in Deelang.")
-
 (defcustom dee-indent-offset 4
   "Default indentation offset for Deelang."
   :group 'dee
@@ -34,14 +28,14 @@
 (defvar dee-font-lock-keywords
   `(,(rx symbol-start
 	 (or
-	  "if" "elif" "else" "")
+	  "if" "elif" "else" "loop" "until" "over" "in" "")
 	 symbol-end)
     (,(rx (group (regexp dee-font-lock-id-re)) (* space) "<-")
      (1 font-lock-variable-name-face))
-    (,(rx (group (regexp dee-font-lock-id-re)) (* space) "->")
-     (1 'dee-function-param-face))
     (,(rx (group (regexp dee-font-lock-id-re)) (* space) "(")
-     (1 font-lock-function-name-face))))
+     (1 font-lock-function-name-face))
+    (,(rx (group (regexp dee-font-lock-id-re)) (* space) "->")
+     (1 font-lock-constant-face))))
 
 (defun dee-indent-line-function ()
   'noindent) ;TODO

demo/buildup.dee

@@ -8,7 +8,7 @@ foo <- ->
     bar()
     baz()
 # functions with block statements
-oo <- x -> y -> x * y + 7 ## Multiple argument functions
+foo <- x -> y -> x * y + 7 ## Multiple argument functions
 if test?()
     do-something()
 elif other-test?()
@@ -23,3 +23,8 @@ else
     if second-test?()
         do-a-real-bad-thing()
 ## Nested blocks
+
+i <- 1
+loop until i > 10
+     print(i)
+     i <- 1

peg.txt

@@ -2,7 +2,8 @@ program		:= __* stmt*
 
 stmt		:= assignment /
 		   funcall stop /
-		   conditional / 
+		   conditional /
+		   loop / 
 		   expr stop
 		   
 expr		:= - _ expr /
@@ -31,6 +32,10 @@ if		:= "if" _ expr block
 elif		:= "elif" _ expr block
 else		:= "else" _ block
 
+loop		:= "loop" _ (until / over / block)
+until 		:= "until" _ expr block
+over		:= "over"_ id "in" _ expr block
+
 block		:= expr / indented_block
 indented_block	:= stop indent __* stmt+ dedent
 

src/emitter.rs

@@ -107,6 +107,7 @@ pub fn emit(w: &mut dyn Write, stmt: &parser::Stmt, ctx: &mut LexicalContext) ->
 		writeln!(w, "}}")?;
 	    }
 	}
+	parser::Stmt::Loop(_) => todo!()
     }
     Ok(())
 }

src/internal.rs

@@ -0,0 +1,3 @@
+//! Internal compiler steps, expansion, cps, optimization.
+
+

src/main.rs

@@ -1,6 +1,7 @@
 mod parser;
 mod evaluator;
 mod emitter;
+mod internal;
 
 use clap::Parser;
 

src/parser.rs

@@ -5,6 +5,7 @@ pub enum Stmt {
     Assignment(String, Expr),
     Funcall(Expr),
     Conditional(Vec<GuardedBlock>, Option<Block>),
+    Loop(Loop),
     BareExpr(Expr),
 }
 
@@ -49,6 +50,13 @@ pub struct GuardedBlock {
     pub block: Block,
 }
 
+#[derive(Debug,PartialEq,Clone)]
+pub enum Loop {
+    Bare(Block),
+    Until(GuardedBlock),
+    Over(String, Expr, Block),
+}
+
 peg::parser! {
     grammar deelang_parser() for str {
         pub rule program() -> Vec<Stmt>
@@ -57,6 +65,7 @@ peg::parser! {
             = a:assignment() { a } /
             f:funcall() stop() { Stmt::Funcall(f) } /
             c:conditional() { c } /
+	    l:_loop() { Stmt::Loop(l) } / 
             e:expr() stop() { Stmt::BareExpr(e) }
         rule expr() -> Expr = precedence! {
 	    e1:(@) "=" _ e2:@ { Expr::Equal(Box::new(e1), Box::new(e2)) }
@@ -114,6 +123,17 @@ peg::parser! {
             }
         rule _else() -> Block
             = "else" _ b:block() { b }
+	rule _loop() -> Loop
+	    = "loop" _ "until" _ e:expr() b:block() __* {
+		Loop::Until(GuardedBlock{
+		    guard:e,
+		    block: b,
+		})
+	    } /
+	    "loop" _ "over" _ i:id() "in" _ e:expr() b:block() __* {
+		Loop::Over(i, e, b)
+	    } /
+	    "loop" _ b:block() __* { Loop::Bare(b) }
         rule block() -> Block
             = i:indented_block() { i } /
 	    e:expr() { vec![Stmt::BareExpr(e)] }