WIP

Author: jemc

main.cr

@@ -77,6 +77,7 @@ 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 "--print-ir", desc: "Print generated LLVM IR", type: Bool, default: false
         option "--print-perf", desc: "Print compiler performance info", type: Bool, default: false
@@ -93,7 +94,11 @@ 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
@@ -199,6 +204,30 @@ 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}"

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