WIP

main.cr

@@ -78,6 +78,7 @@ module Savi
         option "-b", "--backtrace", desc: "Show backtrace on error", type: Bool, default: false
         option "-r", "--release", desc: "Compile in release mode", type: Bool, default: false
         option "--fix", desc: "Auto-fix compile errors where possible", type: Bool, default: false
+        option "--watch", desc: "Run continuously, watching for file changes (EXPERIMENTAL)", type: Bool, default: false
         option "--no-debug", desc: "Compile without debug info", type: Bool, default: false
         option "--llvm-ir", desc: "Write generated LLVM IR to a file", type: Bool, default: false
         option "--llvm-keep-fns", desc: "Don't allow LLVM to remove functions from the output", type: Bool, default: false
@@ -96,7 +97,11 @@ module Savi
           options.target_pass = Savi::Compiler.pass_symbol(opts.pass) if opts.pass
           options.manifest_name = args.name.not_nil! if args.name
           Dir.cd(opts.cd.not_nil!) if opts.cd
-          Cli.run options, opts.backtrace
+          if opts.watch
+            Cli.run_with_watch(options, opts.backtrace)
+          else
+            Cli.run(options, opts.backtrace)
+          end
         end
       end
       sub "build" do
@@ -302,6 +307,30 @@ module Savi
       end
     end
 
+    # This feature is experimental - it's currently not quite working,
+    # due to some issues with inaccurate or incomplete caching of passes.
+    # Also, it doesn't watch precisely the right set of files -
+    # ideally it would watch all of the package globs that are in use,
+    # as well as the manifest files where those packages are defined.
+    # Once we get those issues ironed out, we should mark it as being
+    # no longer experimental, and publicize it as a recommended way of working.
+    def self.run_with_watch(options, backtrace = false)
+      ctx = Savi.compiler.compile(Dir.current, options.target_pass || :run, options)
+      finish_with_errors(ctx.errors, backtrace) if ctx.errors.any?
+      last_compiled_at = Time.utc
+
+      FSWatch.watch(".", latency: 0.25, recursive: true) do |event|
+        next unless event.created? || event.updated? || event.removed? || event.renamed?
+        next if event.timestamp < last_compiled_at
+
+        ctx = Savi.compiler.compile(Dir.current, options.target_pass || :run, options)
+        finish_with_errors(ctx.errors, backtrace) if ctx.errors.any?
+        last_compiled_at = Time.utc
+      end
+
+      sleep
+    end
+
     def self.eval(code, options, backtrace = false)
       _add_backtrace backtrace do
         dirname = "/tmp/savi-eval-#{Random::Secure.hex}"

spec/parser_spec.cr

@@ -14,7 +14,7 @@ describe Savi::Parser do
         c * 9 / 5 + 32.0
     SOURCE
 
-    ast = Savi::Parser.parse(source)
+    ast = Savi::Parser.parse(nil, source)
 
     ast.to_a.pretty_inspect(74).should eq <<-AST
     [:doc,
@@ -65,7 +65,7 @@ describe Savi::Parser do
         ~x
     SOURCE
 
-    ast = Savi::Parser.parse(source)
+    ast = Savi::Parser.parse(nil, source)
 
     # Can't use array literals here because Crystal is too slow to compile them.
     # See https://github.com/crystal-lang/crystal/issues/5792
@@ -181,7 +181,7 @@ describe Savi::Parser do
     MSG
 
     expect_raises Savi::Error, expected do
-      Savi::Parser.parse(source)
+      Savi::Parser.parse(nil, source)
     end
   end
 
@@ -205,7 +205,7 @@ describe Savi::Parser do
         >>>
     SOURCE
 
-    ast = Savi::Parser.parse(source)
+    ast = Savi::Parser.parse(nil, source)
 
     ast.to_a.should eq [:doc,
       [:declare, [:ident, "actor"], [:ident, "Main"]],
@@ -226,7 +226,7 @@ describe Savi::Parser do
       :const y U64: -1
     SOURCE
 
-    ast = Savi::Parser.parse(source)
+    ast = Savi::Parser.parse(nil, source)
 
     # Can't use array literals here because Crystal is too slow to compile them.
     ast.to_a.pretty_inspect(74).should eq <<-AST
@@ -245,8 +245,8 @@ describe Savi::Parser do
       :const greeting String: "Hello, World!"
     SOURCE
 
-    ast1 = Savi::Parser.parse(Savi::Source.new_example(content))
-    ast2 = Savi::Parser.parse(Savi::Source.new_example(content))
+    ast1 = Savi::Parser.parse(nil, Savi::Source.new_example(content))
+    ast2 = Savi::Parser.parse(nil, Savi::Source.new_example(content))
 
     ast1.should be ast2
   end

src/savi/compiler.cr

@@ -261,7 +261,7 @@ class Savi::Compiler
 
     docs = sources.compact_map do |source|
       begin
-        Parser.parse(source)
+        Parser.parse(ctx, source)
       rescue err : Pegmatite::Pattern::MatchError
         pos = Source::Pos.point(source, err.offset)
         ctx.errors << Error.build(pos, "The source code syntax is invalid near here")

src/savi/compiler/context.cr

@@ -80,7 +80,7 @@ class Savi::Compiler::Context
     return package if package
 
     sources = compiler.source_service.get_directory_sources(path, source_package)
-    docs = sources.map { |source| Parser.parse(source) }
+    docs = sources.map { |source| Parser.parse(self, source) }
     compile_package(source_package, docs)
   end
 
@@ -90,14 +90,14 @@ class Savi::Compiler::Context
 
     # Otherwise go ahead and load the manifests.
     sources = compiler.source_service.get_manifest_sources_at(path)
-    docs = sources.map { |source| Parser.parse(source) }
+    docs = sources.map { |source| Parser.parse(self, source) }
     package = compile_package(sources.first.package, docs)
     self
   end
 
   def compile_package(manifest : Packaging::Manifest)
     sources = compiler.source_service.get_sources_for_manifest(self, manifest)
-    docs = sources.map { |source| Parser.parse(source) }
+    docs = sources.map { |source| Parser.parse(self, source) }
     sources << Source.none if sources.empty?
     compile_package(sources.first.package, docs)
   end
@@ -119,6 +119,8 @@ class Savi::Compiler::Context
     if (cache_result = @@cache[source_package.path]?; cache_result)
       cached_docs, cached_package = cache_result
       return cached_package if cached_docs == docs
+
+      puts "    RERUN . compile_package #{source_package.path}" if self.options.print_perf
     end
 
     compile_package_docs(Program::Package.new(source_package), docs)

src/savi/compiler/macros.cr

@@ -25,7 +25,7 @@ class Savi::Compiler::Macros < Savi::AST::CopyOnMutateVisitor
     cached_hash, cached_func = cache_result if cache_result
     return cached_func if cached_func && cached_hash == input_hash
 
-    puts "    RERUN . #{self.class} #{f_link.show}" if cache_result && ctx.options.print_perf
+    puts "    RERUN . #{self} #{f_link.show}" if cache_result && ctx.options.print_perf
 
     yield
 

src/savi/compiler/populate.cr

@@ -191,7 +191,7 @@ class Savi::Compiler::Populate
       cached_hash, cached_func = cache_result if cache_result
       return cached_func if cached_func && cached_hash == input_hash
 
-      puts "    RERUN . #{self.class} #{f_link.show}" if cache_result && ctx.options.print_perf
+      puts "    RERUN . #{self} #{f_link.show}" if cache_result && ctx.options.print_perf
 
       yield
 

src/savi/compiler/reparse.cr

@@ -25,7 +25,7 @@ class Savi::Compiler::Reparse < Savi::AST::CopyOnMutateVisitor
     cached_hash, cached_func = cache_result if cache_result
     return cached_func if cached_func && cached_hash == input_hash
 
-    puts "    RERUN . #{self.class} #{f_link.show}" if cache_result && ctx.options.print_perf
+    puts "    RERUN . #{self} #{f_link.show}" if cache_result && ctx.options.print_perf
 
     yield
 
@@ -42,7 +42,7 @@ class Savi::Compiler::Reparse < Savi::AST::CopyOnMutateVisitor
     t_cached_hash, t_cached_type = t_cache_result if t_cache_result
     return t_cached_type if t_cached_type && t_cached_hash == input_hash
 
-    puts "    RERUN . #{self.class} #{t_link.show}" if t_cache_result && ctx.options.print_perf
+    puts "    RERUN . #{self} #{t_link.show}" if t_cache_result && ctx.options.print_perf
 
     yield
 
@@ -59,7 +59,7 @@ class Savi::Compiler::Reparse < Savi::AST::CopyOnMutateVisitor
     ta_cached_hash, ta_cached_type = ta_cache_result if ta_cache_result
     return ta_cached_type if ta_cached_type && ta_cached_hash == input_hash
 
-    puts "    RERUN . #{self.class} #{t_link.show}" if ta_cache_result && ctx.options.print_perf
+    puts "    RERUN . #{self} #{t_link.show}" if ta_cache_result && ctx.options.print_perf
 
     yield
 

src/savi/compiler/sugar.cr

@@ -20,7 +20,7 @@ class Savi::Compiler::Sugar < Savi::AST::CopyOnMutateVisitor
     cached_hash, cached_func = cache_result if cache_result
     return cached_func if cached_func && cached_hash == input_hash
 
-    puts "    RERUN . #{self.class} #{f_link.show}" if cache_result && ctx.options.print_perf
+    puts "    RERUN . #{self} #{f_link.show}" if cache_result && ctx.options.print_perf
 
     yield
 

src/savi/ext/fswatch/event.cr

@@ -0,0 +1,6 @@
+# Add a timestamp property to all FSWatch events, so that we can track
+# when the event was received by the thread that received it, rather than
+# the time when we got around to first noticing it in our processing loop.
+struct FSWatch::Event
+  property timestamp : Time = Time.utc
+end

src/savi/parser.cr

@@ -2,10 +2,12 @@ require "pegmatite"
 
 module Savi::Parser
   @@cache = {} of String => {Source, AST::Document}
-  def self.parse(source : Source)
+  def self.parse(ctx, source : Source)
     if (cache_result = @@cache[source.path]?; cache_result)
       cached_source, cached_ast = cache_result
       return cached_ast if cached_source == source
+
+      puts "    RERUN . #{self} #{source.path}" if ctx.try(&.options.print_perf)
     end
 
     grammar =
@@ -14,6 +16,7 @@ module Savi::Parser
       else raise NotImplementedError.new("#{source.language} language parsing")
       end
 
+    puts "    RUN . #{self} #{source.path}" if ctx.try(&.options.print_perf)
     Builder.build(Pegmatite.tokenize(grammar, source.content), source)
 
     .tap do |result|