disco 0.1.4 → 0.1.5

raw patch · 9 files changed

+83/−6 lines, 9 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• CHANGELOG.md +7/−0
• disco.cabal +7/−1
• src/Disco/Parser.hs +27/−5
• test/error-parse-RHS/expected +14/−0
• test/error-parse-RHS/input +5/−0
• test/error-unbound/expected +1/−0
• test/error-unbound/input +2/−0
• test/types-306/expected +13/−0
• test/types-306/input +7/−0

@@ -1,3 +1,10 @@+* 0.1.5 (12 March 2022)++  - Syntax errors in function definitions now result in much more+    helpful error messages.  Before, it would just complain about+    something being wrong with the '=' sign.+    ([#346](https://github.com/disco-lang/disco/issues/346))+ * 0.1.4 (10 March 2022)    - New features or syntax

@@ -1,6 +1,6 @@ cabal-version:       2.4 name:                disco-version:             0.1.4+version:             0.1.5 synopsis:            Functional programming language for teaching discrete math. description:         Disco is a simple functional programming language for use in                      teaching discrete math.  Its syntax is designed to be close@@ -98,6 +98,8 @@                      test/error-numpatterns/expected                      test/error-numpatterns/input                      test/error-numpatterns/numpatterns.disco+                     test/error-parse-RHS/expected+                     test/error-parse-RHS/input                      test/error-pattype/expected                      test/error-pattype/input                      test/error-polyrec/expected@@ -109,6 +111,8 @@                      test/error-tyargs/error-tyargs.disco                      test/error-tyargs/expected                      test/error-tyargs/input+                     test/error-unbound/expected+                     test/error-unbound/input                      test/error-unboundtyvar/expected                      test/error-unboundtyvar/input                      test/error-unboundtyvar/unboundtyvar.disco@@ -309,6 +313,8 @@                      test/syntax-types/input                      test/types-192/expected                      test/types-192/input+                     test/types-306/expected+                     test/types-306/input                      test/types-bind/expected                      test/types-bind/input                      test/types-char-string/expected

@@ -461,9 +461,26 @@ parseTopLevel :: Parser TopLevel parseTopLevel = L.nonIndented sc $       TLDoc  <$> parseDocThing-  <|> TLDecl <$> try parseDecl+  <|> TLDecl <$> parseDecl         -- See Note [Parsing definitions and top-level expressions]   <|> TLExpr <$> thenIndented parseTerm +  -- ~~~~ Note [Parsing definitions and top-level expressions]+  --+  -- The beginning of a definition might look the same as an+  -- expression.  e.g. is f(x,y) the start of a definition of f, or an+  -- expression with a function call?  We used to therefore wrap+  -- 'parseDecl' in 'try'.  The problem is that if a definition has a+  -- syntax error on the RHS, it would fail, backtrack, then try+  -- parsing a top-level expression and fail when it got to the =+  -- sign, giving an uninformative parse error message.+  -- See https://github.com/disco-lang/disco/issues/346.+  --+  -- The solution is that we now do more careful backtracking within+  -- parseDecl itself: when parsing a definition, we only backtrack if+  -- we don't get a complete LHS + '=' sign; once we start parsing the+  -- RHS of a definition we no longer backtrack, since it can't+  -- possibly be a valid top-level expression.+ -- | Parse a documentation item: either a group of lines beginning --   with @|||@ (text documentation), or a group beginning with @!!!@ --   (checked examples/properties).@@ -507,10 +524,15 @@ -- | Parse a definition of the form @x pat1 .. patn = t@. parseDefn :: Parser TermDefn parseDefn = label "definition" $-  TermDefn-  <$> ident-  <*> indented ((:[]) <$> (bind <$> many parseAtomicPattern <*> (symbol "=" *> parseTerm)))+  (\(x, ps) body -> TermDefn x [bind ps body]) +  -- Only backtrack if we don't get a complete 'LHS ='.  Once we see+  -- an = sign, commit to parsing a definition, because it can't be a+  -- valid standalone expression anymore.  If the RHS fails, we don't+  -- want to backtrack, we just want to display the parse error.+  <$> try ((,) <$> ident <*> indented (many parseAtomicPattern) <* reservedOp "=")+  <*> indented parseTerm+ -- | Parse the definition of a user-defined algebraic data type. parseTyDefn :: Parser TypeDefn parseTyDefn = label "type defintion" $ do@@ -518,7 +540,7 @@   indented $ do     name <- parseTyDef     args <- fromMaybe [] <$> optional (parens $ parseTyVarName `sepBy1` comma)-    _ <- symbol "="+    _ <- reservedOp "="     TypeDefn name args <$> parseType  -- | Parse the entire input as a term (with leading whitespace and

@@ -0,0 +1,14 @@+1:11:+  |+1 | f(x) = x ++  |           ^+unexpected end of input+expecting expression or operator++1:18:+  |+1 | g(x) = {? 5 if x =< 5, 6 otherwise ?}+  |                  ^^+unexpected "=<"+expecting "?}", "if", "let", "when", ',', expression, operator, or type annotation+

@@ -0,0 +1,5 @@+f : N -> N+f(x) = x +++g : N -> N+g(x) = {? 5 if x =< 5, 6 otherwise ?}

@@ -0,0 +1,1 @@+Error: encountered undefined name REPL.even. Maybe you haven't defined it yet?

@@ -0,0 +1,2 @@+even : Z -> Bool+even(2)

@@ -0,0 +1,13 @@+Error: the shape of two types does not match.+https://disco-lang.readthedocs.io/en/latest/reference/shape-mismatch.html+Error: the shape of two types does not match.+https://disco-lang.readthedocs.io/en/latest/reference/shape-mismatch.html+Error: values of type Bool → Bool cannot be compared.+https://disco-lang.readthedocs.io/en/latest/reference/not-qual.html+Error: values of type a5 → a6 cannot be compared.+https://disco-lang.readthedocs.io/en/latest/reference/not-qual.html+Error: the shape of two types does not match.+https://disco-lang.readthedocs.io/en/latest/reference/shape-mismatch.html+Error: the shape of two types does not match.+https://disco-lang.readthedocs.io/en/latest/reference/shape-mismatch.html+{}

@@ -0,0 +1,7 @@+set [\x.x : Bool -> Bool, \x. not x]+{\x.x : Bool -> Bool, \x. not x}+{\x.x, \x. not x} : Set (Bool -> Bool)+{\x.x, \x. not x}+bag [\x.x : Bool -> Bool, \x. not x]+[\x.x : Bool -> Bool, \x. not x]+{} : Set (Bool -> Bool)