Let in expressions (#1130)

Enhancements:
- Allow variables to be defined within expressions with `let` `in` (see #1126)

.config/dotnet-tools.json

@@ -15,7 +15,7 @@
       ]
     },
     "ghul.compiler": {
-      "version": "0.8.23",
+      "version": "0.8.24",
       "commands": [
         "ghul-compiler"
       ]

Directory.Build.props

@@ -1,6 +1,6 @@
 <Project>
   <PropertyGroup>
-    <Version>0.8.24-alpha.12</Version>
+    <Version>0.8.25-alpha.2</Version>
     <NoWarn>$(NoWarn);NU1507</NoWarn>
   </PropertyGroup>
   <ItemGroup>

integration-tests/execution/let-in-1/.vscode/tasks.json

@@ -0,0 +1,23 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Run test",
+            "command": "dotnet ghul-test \"${workspaceFolder}\"",
+            "type": "shell",
+            "group": {
+                "kind": "test",
+                "isDefault": true
+            }
+        },
+        {
+            "label": "Capture test expectation",
+            "command": "../../../tasks/capture.sh \"${workspaceFolder}\"",
+            "type": "shell",
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        }
+    ]
+}

integration-tests/execution/let-in-1/ghul.json

@@ -0,0 +1,6 @@
+{
+    "compiler": "../../../bin/Release/net8.0/ghul",
+    "source": [
+        "."
+    ]
+}

integration-tests/execution/let-in-1/ghulflags

@@ -0,0 +1 @@
+--dotnet

integration-tests/execution/let-in-1/run.expected

@@ -0,0 +1,13 @@
+simple_expression_body(5) = 10
+simple_expression_body((5, 6)) = 11
+fib(0) = 0
+fib(1) = 1
+fib(2) = 1
+fib(3) = 2
+fib(4) = 3
+fib(5) = 5
+if_expression_condition_1(5) = 5 * 2 more than 10
+if_expression_condition_2(5, 6) = 5 * 2 and 6 * 2 more than 10
+generator_1().take(5).to_list() = 0, 1, 2, 3, 4
+generator_fibonacci().take(5).to_list() = 0, 1, 1, 2, 3
+generator_factorial().take(5).to_list() = 1, 2, 6, 24, 120

integration-tests/execution/let-in-1/test.ghul

@@ -0,0 +1,115 @@
+use IO.Std.write_line;
+
+entry() is
+    write_line("simple_expression_body(5) = " + simple_expression_body_1(5)); // 10
+    write_line("simple_expression_body((5, 6)) = " + simple_expression_body_2((5, 6))); // 11
+    recursive_anonymous_function();
+
+    write_line("if_expression_condition_1(5) = " + if_expression_condition_1(5)); // 5 * 2 less than 10
+    write_line("if_expression_condition_2(5, 6) = " + if_expression_condition_2(5, 6)); // 5 * 2 less than 10
+
+    write_line("generator_1().take(5).to_list() = " + generator_incremental() | .take(5)); // [0, 1, 2, 3, 4]
+    write_line("generator_fibonacci().take(5).to_list() = " + generator_fibonacci() | .take(5)); // [0, 1, 1, 2, 3]
+    write_line("generator_factorial().take(5).to_list() = " + generator_factorial() | .take(5)); // [1, 1, 2, 6, 24]
+si
+
+simple_expression_body_1(i: int) -> int =>
+    let times_2 = i * 2
+    in times_2;
+
+simple_expression_body_2(i: (int, int)) -> int =>
+    let (a, b) = i
+    in a + b;
+
+recursive_anonymous_function() is
+    let fib = (n: int) -> int rec =>
+        let fib = rec in
+        if n < 2 then
+            n
+        else
+            fib(n - 1) + fib(n - 2);
+        fi;
+
+    for (i, f) in (0..6) | .map(i => fib(i)) .index() do
+        write_line("fib(" + i + ") = " + f);
+    od
+si
+
+generator_incremental() -> Collections.Iterable[int] =>
+    generate(0, 
+        (i: int) =>
+            let next = i + 1 in (next, i)); 
+
+generator_fibonacci() -> Collections.Iterable[int] =>
+    generate((0, 1), 
+        (state: (int, int)) =>
+            let 
+                (a, b) = state,
+                next = (b, a + b)
+            in (next, a));
+
+generator_factorial() -> Collections.Iterable[int] =>
+    generate((1, 1), 
+        (state: (int, int)) =>
+            let 
+                (i, f) = state,
+                next = (i + 1, f * (i + 1))
+            in (next, f));
+
+if_expression_condition_1(i: int) -> string =>
+    if 
+        let x = i * 2 in x < 10    
+    then
+        "{i} * 2 less than 10"
+    else
+        "{i} * 2 more than 10"
+    fi;
+
+if_expression_condition_2(i: int, j: int) -> string =>
+    if 
+        let x = i * 2 in x < 10    
+    then
+        "{i} * 2 less than 10"
+    elif
+        let y = j * 2 in y < 10
+    then
+        "{j} * 2 less than 10"
+    else
+        "{i} * 2 and {j} * 2 more than 10"
+    fi;
+
+
+class GENERATOR[T, S]: Collections.Iterator[T], Collections.Iterable[T] is
+    current: T;
+    iterator: Collections.Iterator[T] => self;
+
+    _initial: S;
+    _state: S;
+    _generator: S -> (S, T); // given the current state, return the next state and the current value
+
+    init(initial: S, generator: S -> (S, T)) is
+        _initial = initial;
+        _generator = generator;
+        reset();
+    si
+
+    init() is
+        reset();
+    si
+
+    move_next() -> bool is
+        (_state, current) = _generator(_state);
+        return true;
+    si
+
+    reset() is
+        _state = _initial;
+    si
+
+    dispose() is
+    si
+si
+
+// generator constructor helper so we don't have to specify types
+generate[T, S](initial: S, generator: S -> (S, T)) -> GENERATOR[T, S] =>
+    new GENERATOR[T, S](initial, generator);

integration-tests/parse/expression-function-with-explicit-type-arguments-3/err.expected

@@ -1,2 +1,2 @@
-test.ghul: 11,37..11,39: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found []
+test.ghul: 11,37..11,39: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found []
 test.ghul: 11,37..11,39: error: syntax error: expected ; but found []

integration-tests/parse/expression-function-with-explicit-type-arguments-6/err.expected

@@ -1,2 +1,2 @@
-test.ghul: 15,37..15,39: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found []
+test.ghul: 15,37..15,39: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found []
 test.ghul: 15,37..15,39: error: syntax error: expected ; but found []

integration-tests/parse/incomplete-call-1/err.expected

@@ -1,3 +1,3 @@
 test.ghul: 7,13..7,17: error: symbol not found: blah
-test.ghul: 8,9..8,11: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 8,9..8,11: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si
 test.ghul: 8,9..8,11: error: in secondary expression: expected ) but found si

integration-tests/parse/incomplete-enum-6/err.expected

@@ -1 +1 @@
-test.ghul: 8,1..8,2: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 8,1..8,2: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si

integration-tests/parse/incomplete-for-10/err.expected

@@ -1 +1 @@
-test.ghul: 2,14..2,16: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found do
+test.ghul: 2,14..2,16: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found do

integration-tests/parse/incomplete-for-3/err.expected

@@ -1 +1 @@
-test.ghul: 4,1..4,3: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 4,1..4,3: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si

integration-tests/parse/incomplete-for-4/err.expected

@@ -1,2 +1,2 @@
 test.ghul: 3,1..3,3: error: in for statement: expected do but found si
-test.ghul: 3,1..3,3: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 3,1..3,3: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si

integration-tests/parse/incomplete-if-1/err.expected

@@ -1 +1 @@
-test.ghul: 8,9..8,11: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 8,9..8,11: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si

integration-tests/parse/incomplete-let-in-1/.vscode/tasks.json

@@ -0,0 +1,23 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Run test",
+            "command": "dotnet ghul-test \"${workspaceFolder}\"",
+            "type": "shell",
+            "group": {
+                "kind": "test",
+                "isDefault": true
+            }
+        },
+        {
+            "label": "Capture test expectation",
+            "command": "../../../tasks/capture.sh \"${workspaceFolder}\"",
+            "type": "shell",
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        }
+    ]
+}

integration-tests/parse/incomplete-let-in-1/err.expected

@@ -0,0 +1,2 @@
+test.ghul: 10,5..10,7: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 10,5..10,7: error: syntax error: expected ; but found si

integration-tests/parse/incomplete-let-in-1/fail.expected

@@ -0,0 +1 @@
+

integration-tests/parse/incomplete-let-in-1/ghul.json

@@ -0,0 +1,6 @@
+{
+    "compiler": "dotnet ../../../publish/ghul.dll",
+    "source": [
+        "."
+    ]
+}

integration-tests/parse/incomplete-let-in-1/ghulflags

@@ -0,0 +1 @@
+--type-check 

integration-tests/parse/incomplete-let-in-1/test.ghul

@@ -0,0 +1,17 @@
+namespace Test.ParseLetIn is
+    use Collections;
+
+    class TestA is
+        test_simple() -> int =>
+            let 
+                x = new D()
+            in
+
+    si
+
+    class D is
+        value: int => 1234;
+        init() is
+        si
+    si
+si

integration-tests/parse/incomplete-let-in-2/.vscode/tasks.json

@@ -0,0 +1,23 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Run test",
+            "command": "dotnet ghul-test \"${workspaceFolder}\"",
+            "type": "shell",
+            "group": {
+                "kind": "test",
+                "isDefault": true
+            }
+        },
+        {
+            "label": "Capture test expectation",
+            "command": "../../../tasks/capture.sh \"${workspaceFolder}\"",
+            "type": "shell",
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        }
+    ]
+}

integration-tests/parse/incomplete-let-in-2/err.expected

@@ -0,0 +1,3 @@
+test.ghul: 8,5..8,7: error: in variable: expected ( or identifier but found si
+test.ghul: 8,5..8,7: error: syntax error: expected ; but found si
+test.ghul: 8,5..8,7: error: syntax error: expected in but found si

integration-tests/parse/incomplete-let-in-2/fail.expected

@@ -0,0 +1 @@
+

integration-tests/parse/incomplete-let-in-2/ghul.json

@@ -0,0 +1,6 @@
+{
+    "compiler": "dotnet ../../../publish/ghul.dll",
+    "source": [
+        "."
+    ]
+}

integration-tests/parse/incomplete-let-in-2/ghulflags

@@ -0,0 +1 @@
+--type-check 

integration-tests/parse/incomplete-let-in-2/test.ghul

@@ -0,0 +1,15 @@
+namespace Test.ParseLetIn is
+    use Collections;
+
+    class TestA is
+        test_simple() -> int =>
+            let 
+
+    si
+
+    class D is
+        value: int => 1234;
+        init() is
+        si
+    si
+si

integration-tests/parse/incomplete-property-14/err.expected

@@ -1,2 +1,2 @@
-test.ghul: 5,5..5,7: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 5,5..5,7: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si
 test.ghul: 5,5..5,7: error: syntax error: expected ; but found si

integration-tests/parse/incomplete-property-15/err.expected

@@ -1,2 +1,2 @@
-test.ghul: 6,5..6,7: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 6,5..6,7: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si
 test.ghul: 6,5..6,7: error: syntax error: expected ; but found si

integration-tests/parse/incomplete-property-3/err.expected

@@ -1,2 +1,2 @@
-test.ghul: 5,5..5,7: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 5,5..5,7: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si
 test.ghul: 5,5..5,7: error: syntax error: expected ; but found si

integration-tests/parse/incomplete-property-4/err.expected

@@ -1,2 +1,2 @@
-test.ghul: 6,5..6,7: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 6,5..6,7: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si
 test.ghul: 6,5..6,7: error: syntax error: expected ; but found si

integration-tests/parse/incomplete-string-interpolation-11/err.expected

@@ -1 +1 @@
-test.ghul: 7,19..7,33: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found }  interpolate
+test.ghul: 7,19..7,33: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found }  interpolate

integration-tests/parse/incomplete-string-interpolation-3/err.expected

@@ -1 +1 @@
-test.ghul: 7,1..7,3: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 7,1..7,3: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si

integration-tests/parse/incomplete-string-interpolation-5/err.expected

@@ -1 +1 @@
-test.ghul: 7,1..7,3: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 7,1..7,3: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si

integration-tests/parse/incomplete-variable-5/err.expected

@@ -1 +1 @@
-test.ghul: 7,9..7,11: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 7,9..7,11: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si

integration-tests/parse/incomplete-variable-6/err.expected

@@ -1 +1 @@
-test.ghul: 7,9..7,11: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, new, null, rec, self, string literal, super, true, typeof or { but found si
+test.ghul: 7,9..7,11: error: in primary expression: expected (, [, cast, char literal, false, float literal, identifier, if, int literal, isa, let, new, null, rec, self, string literal, super, true, typeof or { but found si

integration-tests/semantic/variable-let-in-1/.vscode/tasks.json

@@ -0,0 +1,23 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Run test",
+            "command": "dotnet ghul-test \"${workspaceFolder}\"",
+            "type": "shell",
+            "group": {
+                "kind": "test",
+                "isDefault": true
+            }
+        },
+        {
+            "label": "Capture test expectation",
+            "command": "../../../tasks/capture.sh \"${workspaceFolder}\"",
+            "type": "shell",
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        }
+    ]
+}

integration-tests/semantic/variable-let-in-1/err.expected

@@ -0,0 +1 @@
+test.ghul: 99,13..99,39: error: let in expression result is not used

integration-tests/semantic/variable-let-in-1/fail.expected

@@ -0,0 +1 @@
+

integration-tests/semantic/variable-let-in-1/ghul.json

@@ -0,0 +1,6 @@
+{
+    "compiler": "dotnet ../../../publish/ghul.dll",
+    "source": [
+        "."
+    ]
+}

integration-tests/semantic/variable-let-in-1/ghulflags

@@ -0,0 +1 @@
+--type-check