Adjust whitespace during WIT printing

crates/wit-component/src/printing.rs

@@ -1,11 +1,16 @@
 use anyhow::{anyhow, bail, Result};
 use std::fmt::{self, Write};
+use std::mem;
 use wit_parser::*;
 
 /// A utility for printing WebAssembly interface definitions to a string.
 #[derive(Default)]
 pub struct WitPrinter {
     output: Output,
+
+    // Count of how many items in this current block have been printed to print
+    // a blank line between each item, but not the first item.
+    any_items: bool,
 }
 
 impl WitPrinter {
@@ -39,8 +44,16 @@ impl WitPrinter {
         Ok(std::mem::take(&mut self.output).into())
     }
 
+    fn new_item(&mut self) {
+        if self.any_items {
+            self.output.push_str("\n");
+        }
+        self.any_items = true;
+    }
+
     /// Print the given WebAssembly interface to a string.
     fn print_interface(&mut self, resolve: &Resolve, id: InterfaceId) -> Result<()> {
+        let prev_items = mem::replace(&mut self.any_items, false);
         let interface = &resolve.interfaces[id];
 
         self.print_types(
@@ -52,16 +65,16 @@ impl WitPrinter {
                 .map(|(name, id)| (name.as_str(), *id)),
         )?;
 
-        for (i, (name, func)) in interface.functions.iter().enumerate() {
-            if i > 0 {
-                self.output.push_str("\n");
-            }
+        for (name, func) in interface.functions.iter() {
+            self.new_item();
             self.print_name(name);
             self.output.push_str(": ");
             self.print_function(resolve, func)?;
             self.output.push_str("\n");
         }
 
+        self.any_items = prev_items;
+
         Ok(())
     }
 
@@ -108,8 +121,8 @@ impl WitPrinter {
             TypeOwner::World(id) => resolve.worlds[id].package.unwrap(),
             TypeOwner::None => unreachable!(),
         };
-        let amt_to_import = types_to_import.len();
         for (owner, tys) in types_to_import {
+            self.any_items = true;
             write!(&mut self.output, "use ")?;
             let id = match owner {
                 TypeOwner::Interface(id) => id,
@@ -134,11 +147,8 @@ impl WitPrinter {
             writeln!(&mut self.output, "}}")?;
         }
 
-        if amt_to_import > 0 && types_to_declare.len() > 0 {
-            self.output.push_str("\n");
-        }
-
         for id in types_to_declare {
+            self.new_item();
             self.declare_type(resolve, &Type::Id(id))?;
         }
 
@@ -182,6 +192,7 @@ impl WitPrinter {
     }
 
     fn print_world(&mut self, resolve: &Resolve, id: WorldId) -> Result<()> {
+        let prev_items = mem::replace(&mut self.any_items, false);
         let world = &resolve.worlds[id];
         let pkgid = world.package.unwrap();
         let mut types = Vec::new();
@@ -193,13 +204,21 @@ impl WitPrinter {
                 },
                 _ => {
                     self.print_world_item(resolve, name, import, pkgid, "import")?;
+                    // Don't put a blank line between imports, but count
+                    // imports as having printed something so if anything comes
+                    // after them then a blank line is printed after imports.
+                    self.any_items = true;
                 }
             }
         }
         self.print_types(resolve, TypeOwner::World(id), types.into_iter())?;
+        if !world.exports.is_empty() {
+            self.new_item();
+        }
         for (name, export) in world.exports.iter() {
             self.print_world_item(resolve, name, export, pkgid, "export")?;
         }
+        self.any_items = prev_items;
         Ok(())
     }
 
@@ -466,7 +485,7 @@ impl WitPrinter {
                             self.print_name(name);
                             self.output.push_str(" = ");
                             self.print_type_name(resolve, inner)?;
-                            self.output.push_str("\n\n");
+                            self.output.push_str("\n");
                         }
                         None => bail!("unnamed type in document"),
                     },
@@ -490,7 +509,7 @@ impl WitPrinter {
                 self.print_name(name);
                 self.output.push_str(" = ");
                 self.print_handle_type(resolve, handle)?;
-                self.output.push_str("\n\n");
+                self.output.push_str("\n");
 
                 Ok(())
             }
@@ -597,7 +616,7 @@ impl WitPrinter {
                     self.print_type_name(resolve, &field.ty)?;
                     self.output.push_str(",\n");
                 }
-                self.output.push_str("}\n\n");
+                self.output.push_str("}\n");
                 Ok(())
             }
             None => bail!("document has unnamed record type"),
@@ -615,7 +634,7 @@ impl WitPrinter {
             self.print_name(name);
             self.output.push_str(" = ");
             self.print_tuple_type(resolve, tuple)?;
-            self.output.push_str("\n\n");
+            self.output.push_str("\n");
         }
         Ok(())
     }
@@ -630,7 +649,7 @@ impl WitPrinter {
                     self.print_name(&flag.name);
                     self.output.push_str(",\n");
                 }
-                self.output.push_str("}\n\n");
+                self.output.push_str("}\n");
             }
             None => bail!("document has unnamed flags type"),
         }
@@ -659,7 +678,7 @@ impl WitPrinter {
             }
             self.output.push_str(",\n");
         }
-        self.output.push_str("}\n\n");
+        self.output.push_str("}\n");
         Ok(())
     }
 
@@ -681,7 +700,7 @@ impl WitPrinter {
             self.print_type_name(resolve, &case.ty)?;
             self.output.push_str(",\n");
         }
-        self.output.push_str("}\n\n");
+        self.output.push_str("}\n");
         Ok(())
     }
 
@@ -696,7 +715,7 @@ impl WitPrinter {
             self.print_name(name);
             self.output.push_str(" = ");
             self.print_option_type(resolve, payload)?;
-            self.output.push_str("\n\n");
+            self.output.push_str("\n");
         }
         Ok(())
     }
@@ -712,7 +731,7 @@ impl WitPrinter {
             self.print_name(name);
             self.output.push_str(" = ");
             self.print_result_type(resolve, result)?;
-            self.output.push_str("\n\n");
+            self.output.push_str("\n");
         }
         Ok(())
     }
@@ -729,7 +748,7 @@ impl WitPrinter {
             self.print_name(&case.name);
             self.output.push_str(",\n");
         }
-        self.output.push_str("}\n\n");
+        self.output.push_str("}\n");
         Ok(())
     }
 
@@ -739,7 +758,7 @@ impl WitPrinter {
             self.print_name(name);
             self.output.push_str(" = list<");
             self.print_type_name(resolve, ty)?;
-            self.output.push_str(">\n\n");
+            self.output.push_str(">\n");
             return Ok(());
         }
 

crates/wit-component/tests/components/adapt-export-reallocs/component.wit.print

@@ -4,5 +4,6 @@ world root {
   import new: interface {
     read: func(amt: u32) -> list<u8>
   }
+
   export entrypoint: func(args: list<string>)
 }

crates/wit-component/tests/components/adapt-import-only-used-in-adapter/component.wit.print

@@ -3,6 +3,7 @@ package root:component
 world root {
   import foo:foo/adapter-imports
   import foo: func(x: string)
+
   export bar: func()
   export adapter-bar: func(x: string)
 }

crates/wit-component/tests/components/bare-funcs/component.wit.print

@@ -3,6 +3,7 @@ package root:component
 world root {
   import foo: func()
   import bar: func() -> string
+
   export baz: func()
   export foo2: func(x: string) -> option<list<u8>>
 }

crates/wit-component/tests/components/ensure-default-type-exports/component.wit.print

@@ -2,5 +2,6 @@ package root:component
 
 world root {
   import foo:foo/foo
+
   export a: func(b: u8)
 }

crates/wit-component/tests/components/export-interface-using-import/component.wit.print

@@ -2,6 +2,7 @@ package root:component
 
 world root {
   import foo:foo/foo
+
   export x: interface {
     use foo:foo/foo.{r}
   }

crates/wit-component/tests/components/export-name-shuffling/component.wit.print

@@ -4,6 +4,7 @@ world root {
   export foo:foo/name
   export name: interface {
     use foo:foo/name.{foo}
+
     a: func(f: foo)
   }
 }

crates/wit-component/tests/components/export-type-name-conflict/component.wit.print

@@ -2,8 +2,10 @@ package root:component
 
 world root {
   import foo:foo/foo
+
   export bar: interface {
     use foo:foo/foo.{foo as bar}
+
     foo: func() -> bar
   }
 }

crates/wit-component/tests/components/import-export-same-iface-name/component.wit.print

@@ -3,5 +3,6 @@ package root:component
 world root {
   import foo:dep/the-name
   import foo:foo/the-name
+
   export foo:foo/the-name
 }

crates/wit-component/tests/components/import-export/component.wit.print

@@ -4,6 +4,7 @@ world root {
   import foo: interface {
     a: func() -> string
   }
+
   export bar: interface {
     a: func()
 

crates/wit-component/tests/components/import-in-adapter-and-main-module/component.wit.print

@@ -5,10 +5,12 @@ world root {
   import foo:shared-dependency/types
   import main-dep: interface {
     use foo:shared-dependency/types.{a-typedef}
+
     foo: func() -> a-typedef
   }
   import adapter-dep: interface {
     use foo:shared-dependency/types.{a-typedef}
+
     foo: func() -> a-typedef
   }
 }

crates/wit-component/tests/components/many-same-names/component.wit.print

@@ -2,9 +2,11 @@ package root:component
 
 world root {
   import foo:foo/name
+
   export foo:foo/name
   export name: interface {
     use foo:foo/name.{r2}
+
     a: func()
   }
 }

crates/wit-component/tests/components/rename-interface/component.wit.print

@@ -4,6 +4,7 @@ world root {
   import foo:foo/foo
   import other-name: interface {
     use foo:foo/foo.{bar}
+
     a: func() -> bar
   }
 }

crates/wit-component/tests/components/tricky-order/component.wit.print

@@ -3,6 +3,7 @@ package root:component
 world root {
   import foo:foo/name1
   import foo:foo/name2
+
   export name: interface {
     use foo:foo/name1.{name}
     use foo:foo/name2.{name as name1}

crates/wit-component/tests/components/worlds-with-type-renamings/component.wit.print

@@ -3,5 +3,6 @@ package root:component
 world root {
   import foo:foo/i
   use foo:foo/i.{some-type as other-name}
+
   export foo:foo/i
 }

crates/wit-component/tests/interfaces/diamond-disambiguate/foo.wit.print

@@ -2,12 +2,10 @@ package foo:foo
 
 interface shared2 {
   type t2 = u8
-
 }
 
 interface shared1 {
   type t1 = u8
-
 }
 
 world w1 {

crates/wit-component/tests/interfaces/diamond.wit.print

@@ -4,11 +4,11 @@ interface shared-items {
   enum the-enum {
     a,
   }
-
 }
 
 world w3 {
   import shared-items
+
   export bar: interface {
     use shared-items.{the-enum}
   }
@@ -18,6 +18,7 @@ world w2 {
   import foo: interface {
     use shared-items.{the-enum}
   }
+
   export bar: interface {
     use shared-items.{the-enum}
   }

crates/wit-component/tests/interfaces/empty.wit.print

@@ -7,6 +7,7 @@ world empty-world {
   import empty
   import empty: interface {
   }
+
   export empty
   export empty2: interface {
   }

crates/wit-component/tests/interfaces/import-and-export.wit.print

@@ -10,5 +10,6 @@ interface bar {
 
 world import-and-export {
   import foo
+
   export bar
 }

crates/wit-component/tests/interfaces/multi-doc/foo.wit.print

@@ -3,7 +3,6 @@ package foo:foo
 interface b {
   record the-type {
   }
-
 }
 
 interface b2 {

crates/wit-component/tests/interfaces/multiple-use.wit.print

@@ -4,12 +4,10 @@ interface foo {
   type t2 = u8
 
   type t1 = u8
-
 }
 
 interface bar {
   type u = u8
-
 }
 
 interface baz {