Change grammar to properly allow if, while, and for loops (without confusing it with closures).

Cargo.lock

@@ -218,9 +218,9 @@ checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
 
 [[package]]
 name = "pest"
-version = "2.7.14"
+version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "879952a81a83930934cbf1786752d6dedc3b1f29e8f8fb2ad1d0a36f377cf442"
+checksum = "198db74531d58c70a361c42201efde7e2591e976d518caf7662a47dc5720e7b6"
 dependencies = [
  "memchr",
  "thiserror",
@@ -229,9 +229,9 @@ dependencies = [
 
 [[package]]
 name = "pest_derive"
-version = "2.7.14"
+version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d214365f632b123a47fd913301e14c946c61d1c183ee245fa76eb752e59a02dd"
+checksum = "d725d9cfd79e87dccc9341a2ef39d1b6f6353d68c4b33c177febbe1a402c97c5"
 dependencies = [
  "pest",
  "pest_generator",
@@ -239,9 +239,9 @@ dependencies = [
 
 [[package]]
 name = "pest_generator"
-version = "2.7.14"
+version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eb55586734301717aea2ac313f50b2eb8f60d2fc3dc01d190eefa2e625f60c4e"
+checksum = "db7d01726be8ab66ab32f9df467ae8b1148906685bbe75c82d1e65d7f5b3f841"
 dependencies = [
  "pest",
  "pest_meta",
@@ -252,9 +252,9 @@ dependencies = [
 
 [[package]]
 name = "pest_meta"
-version = "2.7.14"
+version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b75da2a70cf4d9cb76833c990ac9cd3923c9a8905a8929789ce347c84564d03d"
+checksum = "7f9f832470494906d1fca5329f8ab5791cc60beb230c74815dff541cbd2b5ca0"
 dependencies = [
  "once_cell",
  "pest",
@@ -338,18 +338,18 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "1.0.69"
+version = "2.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b6aaf5339b578ea85b50e080feb250a3e8ae8cfcdff9a461c9ec2904bc923f52"
+checksum = "567b8a2dae586314f7be2a752ec7474332959c6460e02bde30d702a66d488708"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "1.0.69"
+version = "2.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
+checksum = "7f7cf42b4507d8ea322120659672cf1b9dbb93f8f2d4ecfd6e51350ff5b17a1d"
 dependencies = [
  "proc-macro2",
  "quote",

Cargo.toml

@@ -12,9 +12,9 @@ name = "dmc"
 path = "src/bin/dmc/main.rs"
 
 [dependencies]
-pest = "2.7.14"
+pest = { version = "2.8.0" }
 clap = { version = "4.5.23", features = ["derive"] }
-pest_derive = "2.7.14"
+pest_derive = { version = "2.8.0", features = ["grammar-extras"] }
 codespan-reporting = "0.12.0"
 log = "0.4.27"
 indoc = "2.0.6"

sketching/may_2025/if.dm

@@ -1,7 +1,7 @@
 fn main(args: Array<String>) {
-    if args[0] == 'test' {
+    if (args[0] == 'test') {
         println('test');
-    } else if args[0] == 'foo' {
+    } else if (args[0] == 'foo') {
         println('foo');
     } else {
         println('not test');

src/ast/build.rs

@@ -941,11 +941,51 @@ fn build_if_else_statement(file_id: usize, if_else_statement_pair: Pair<Rule>) -
 }
 
 fn build_while_statement(file_id: usize, while_statement_pair: Pair<Rule>) -> WhileStatement {
-    todo!()
+    let mut inner = while_statement_pair.into_inner();
+    inner.next().unwrap(); // while
+    let condition = expect_and_use(
+        file_id,
+        inner.next().unwrap(),
+        Rule::Expression,
+        build_expression,
+    );
+
+    let body = expect_and_use(
+        file_id,
+        inner.next().unwrap(),
+        Rule::BlockStatement,
+        build_block_statement,
+    );
+    WhileStatement { condition, body }
 }
 
 fn build_for_statement(file_id: usize, for_statement_pair: Pair<Rule>) -> ForStatement {
-    todo!()
+    let mut inner = for_statement_pair.into_inner();
+    inner.next().unwrap(); // for
+    let variable = expect_and_use(
+        file_id,
+        inner.next().unwrap(),
+        Rule::Identifier,
+        build_identifier,
+    );
+    inner.next().unwrap(); // in
+    let iterator = expect_and_use(
+        file_id,
+        inner.next().unwrap(),
+        Rule::Expression,
+        build_expression,
+    );
+    let body = expect_and_use(
+        file_id,
+        inner.next().unwrap(),
+        Rule::BlockStatement,
+        build_block_statement,
+    );
+    ForStatement {
+        variable,
+        iterator,
+        body,
+    }
 }
 
 fn build_expression(file_id: usize, expression_pair: Pair<Rule>) -> Expression {
@@ -1514,7 +1554,11 @@ mod tests {
         if let Err(e) = parse_result {
             panic!("Parsing failed.\n{}", e)
         } else {
-            let ast = build_ast(0, parse_result.unwrap().next().unwrap());
+            let mut pairs = parse_result.unwrap();
+            if pairs.as_str().trim() != src.trim() {
+                panic!("Parsing did not consume entire input.");
+            }
+            let ast = build_ast(0, pairs.next().unwrap());
             dbg!(ast);
         }
     }
@@ -1576,7 +1620,7 @@ mod tests {
     fn if_statement() {
         assert_builds(indoc! {"
             fn main() {
-                if true {
+                if (true) {
                     foo
                 }
             }
@@ -1587,7 +1631,7 @@ mod tests {
     fn if_else_statement() {
         assert_builds(indoc! {"
             fn main() {
-                if true {
+                if (true) {
                     foo
                 } else {
                     bar
@@ -1600,9 +1644,9 @@ mod tests {
     fn if_else_if_statement() {
         assert_builds(indoc! {"
             fn main() {
-                if true {
+                if (true) {
                     foo
-                } else if false {
+                } else if (false) {
                     bar
                 }
             }
@@ -1613,9 +1657,9 @@ mod tests {
     fn if_else_if_else_statement() {
         assert_builds(indoc! {"
             fn main() {
-                if true {
+                if (true) {
                     foo
-                } else if false {
+                } else if (false) {
                     bar
                 } else {
                     buzz
@@ -1623,4 +1667,59 @@ mod tests {
             }
         "})
     }
+
+    #[test]
+    fn while_statement() {
+        assert_builds(indoc! {"
+            fn main() {
+                while (true) {
+                    foo()
+                }
+            }
+        "})
+    }
+
+    #[test]
+    fn for_statement() {
+        assert_builds(indoc! {"
+            fn main(args: Array<String>) {
+                for (arg in args) {
+                    foo(arg);
+                }
+            }
+        "})
+    }
+    
+    #[test]
+    fn if_with_call_condition() {
+        assert_builds(indoc! {"
+            fn main() {
+                if (foo()) {
+                    bar()
+                }
+            }
+        "})
+    }
+    
+    #[test]
+    fn while_with_call_condition() {
+        assert_builds(indoc! {"
+            fn main() {
+                while (foo()) {
+                    bar()
+                }
+            }
+        "})
+    }
+    
+    #[test]
+    fn for_with_call_iterator() {
+        assert_builds(indoc! {"
+            fn main() {
+                for (foo in bar()) {
+                    baz(foo)
+                }
+            }
+        "})
+    }
 }

src/ast/unparse.rs

@@ -824,9 +824,9 @@ impl Unparse for ReturnStatement {
 
 impl Unparse for IfStatement {
     fn unparse(&self, writer: &mut IndentWriter) -> std::io::Result<()> {
-        writer.write_indented("if ")?;
+        writer.write_indented("if (")?;
         self.condition.unparse(writer)?;
-        writer.writeln(" {")?;
+        writer.writeln(") {")?;
         self.then_block.unparse_inner(writer)?;
         writer.writeln_indented("}")?;
         Ok(())
@@ -847,9 +847,9 @@ impl Unparse for IfElseStatement {
 impl Unparse for ElseIfs {
     fn unparse(&self, writer: &mut IndentWriter) -> std::io::Result<()> {
         for if_statement in &self.0 {
-            writer.write_indented("else if ")?;
+            writer.write_indented("else if (")?;
             if_statement.condition.unparse(writer)?;
-            writer.writeln(" {")?;
+            writer.writeln(") {")?;
             if_statement.then_block.unparse_inner(writer)?;
             writer.writeln_indented("}")?;
         }

src/parser/deimos.pest

@@ -536,7 +536,9 @@ ReturnStatement = {
 
 IfStatement = {
       If
+    ~ "("
     ~ Expression
+    ~ ")"
     ~ BlockStatement
 }
 
@@ -558,15 +560,19 @@ ElseBlock = {
 
 WhileStatement = {
       While
+    ~ "("
     ~ Expression
+    ~ ")"
     ~ BlockStatement
 }
 
 ForStatement = {
       For
-    ~ Expression
+    ~ "("
+    ~ Identifier
     ~ In
     ~ Expression
+    ~ ")"
     ~ BlockStatement
 }
 

src/parser/mod.rs

@@ -8,7 +8,7 @@ pub struct DeimosParser;
 mod deimos_parser_tests {
     use crate::parser::{DeimosParser, Rule};
     use indoc::indoc;
-    use pest::Parser;
+    use pest::{parses_to, Parser};
 
     macro_rules! fail_rule {
         ($pair: expr; $rule:path) => {{
@@ -34,7 +34,7 @@ mod deimos_parser_tests {
             panic!("Parsing failed.\n{}", e);
         } else {
             let mut pairs = parse_result.unwrap();
-            if input != pairs.as_str() {
+            if input.trim() != pairs.as_str().trim() {
                 panic!(
                     "Parsing did not consume entire input. Consumed only:\n{}",
                     pairs.as_str()
@@ -101,7 +101,7 @@ mod deimos_parser_tests {
         parses_to(
             Rule::IfStatement,
             indoc! {"
-            if foo == 42 {
+            if (foo == 42) {
                 bar()
             }"},
         )
@@ -112,7 +112,7 @@ mod deimos_parser_tests {
         parses_to(
             Rule::IfElseStatement,
             indoc! {"
-            if foo == 42 {
+            if (foo == 42) {
                 bar()
             } else {
                 baz()
@@ -125,9 +125,9 @@ mod deimos_parser_tests {
         parses_to(
             Rule::IfElseStatement,
             indoc! {"
-            if foo == 42 {
+            if (foo == 42) {
                 bar()
-            } else if foo == 16 {
+            } else if (foo == 16) {
                 baz()
             }"},
         )
@@ -138,13 +138,46 @@ mod deimos_parser_tests {
         parses_to(
             Rule::IfElseStatement,
             indoc! {"
-            if foo == 42 {
+            if (foo == 42) {
                 foo()
-            } else if foo == 16 {
+            } else if (foo == 16) {
                 baz()
             } else {
                 fizz()
             }"},
         )
     }
+    
+    #[test]
+    fn while_statement() {
+        parses_to(Rule::WhileStatement, "while (foo) { bar() }");
+    }
+    
+    #[test]
+    fn for_statement() {
+        parses_to(Rule::ForStatement, "for (foo in bar) { baz(foo); }");
+    }
+    
+    #[test]
+    fn if_statement_with_call_condition() {
+        parses_to(Rule::IfStatement, indoc! {"
+            if (foo()) {
+                bar()
+            }
+        "})
+    }
+    
+    #[test]
+    fn while_statement_with_call_condition() {
+        parses_to(Rule::WhileStatement, "while (foo()) { bar(); }")
+    }
+    
+    #[test]
+    fn for_statement_with_call_iterator() {
+        parses_to(Rule::ForStatement, indoc! {"
+            for (foo in bar()) {
+                baz(foo);
+            }
+        "})
+    }
 }