AST-36 Allow (cascaded) tuple projections

README.md

@@ -181,6 +181,9 @@ and open the path printed on the last line of that command.
   - `[T]`
   - `[var T]`
 
+* Tuple types: heterogeneous aggregates of fixed size
+  - `(Bool, Float, Text)`
+
 * Option types: ML/Haskell-style option/maybe type, other types do not include null!
   - `? T`
 
@@ -231,6 +234,7 @@ and open the path printed on the last line of that command.
   - `[3, 4]`
   - `o.x`
   - `a[i]`
+  - `tuple.0`
 
 * Function calls, short-cut return
   - `f(x, y)`

src/lexer.mll

@@ -163,6 +163,7 @@ rule token mode = parse
   | "->" { ARROW }
   | "_" { UNDERSCORE }
 
+  | '.' (num as s) { DOT_NUM s }
   | nat as s { NAT s }
   | float as s { FLOAT s }
   | char as s { CHAR (char lexbuf s) }

src/parser.mly

@@ -107,6 +107,7 @@ let share_expfield (ef : exp_field) =
 %token PLUSASSIGN MINUSASSIGN MULASSIGN DIVASSIGN MODASSIGN POWASSIGN CATASSIGN
 %token ANDASSIGN ORASSIGN XORASSIGN SHLASSIGN SHRASSIGN ROTLASSIGN ROTRASSIGN
 %token NULL
+%token<string> DOT_NUM
 %token<string> NAT
 %token<string> FLOAT
 %token<Value.unicode> CHAR
@@ -348,7 +349,7 @@ exp_post :
     { ArrayE(m, es) @? at $sloc }
   | e1=exp_post LBRACKET e2=exp RBRACKET
     { IdxE(e1, e2) @? at $sloc }
-  | e=exp_post DOT s=NAT
+  | e=exp_post s=DOT_NUM
     { ProjE (e, int_of_string s) @? at $sloc }
   | e=exp_post DOT x=id
     { DotE(e, dummy_obj_sort(), {x with it = Name x.it}) @? at $sloc }

test/fail/issue36.as

@@ -0,0 +1,29 @@
+// AST-36: foo.bar.1.zap won't parse
+
+type Z = { zap : Nat };
+type B = { bar : (Int, Z) };
+
+let inner : Z = new { zap = 42 };
+let foo : B = new { bar = (25, inner) };
+
+assert(foo.bar.0 == 25);
+
+assert(foo.bar.1.zap == 42);
+
+assert((0,((1,1,2), (3,5), 8), 12).1.1.1 == 5);
+
+// Slight imbalance: between DOT and ID we can have whitespace...
+
+assert(foo. bar .1 . zap == 42);
+
+// but not between DOT and NUM:
+
+// assert(foo.bar. 2.zap == 42) // Error
+
+// N.B.: We did not change the FLOAT syntax:
+
+let (f, g, h) : (Float, Float, Float) = (1., 1.7, 1.8e-4);
+
+// N.B. these fail in wasm (AST-40)
+
+let (k, l) : (Float, Float) = (0x644., 0x644.5P-1)

test/fail/ok/issue36.wasm-run.ok

@@ -0,0 +1 @@
+_out/issue36.wasm:0x___: runtime trap: unreachable executed

test/fail/ok/issue36.wasm.stderr.ok

@@ -0,0 +1,5 @@
+compile_lit: (FloatLit 1.)
+compile_lit: (FloatLit 1.7)
+compile_lit: (FloatLit 0.000_18)
+compile_lit: (FloatLit 1_604.)
+compile_lit: (FloatLit 802.156_25)