oselect: WIP, nothing done yet.

shard.yml

@@ -20,5 +20,7 @@ targets:
     main: src/osh/main.cr
   ofind:
     main: src/ofind/main.cr
+  oselect:
+    main: src/oselect/main.cr
 
 license: ISC

src/oselect/main.cr

@@ -0,0 +1,96 @@
+require "option_parser"
+require "json"
+require "cbor"
+
+class Context
+	class_property is_json = false
+end
+
+# # XXX
+# class Action
+# 	property command : Proc(v : JSON::Any | CBOR::Any, Bool)
+# end
+
+class SelectApplication
+	property to_search = Array(String).new
+
+	def initialize
+	end
+
+	def run
+		OptionParser.parse do |parser|
+			parser.banner = "usage: select [options] filters"
+
+			parser.on "-j", "--json", "Input is JSON." do
+				Context.is_json = true
+			end
+
+			parser.on "-h", "--help", "Displays this help and exits." do
+				puts parser
+				exit 0
+			end
+		end
+
+		# 1. Get intent from CLI.
+		if ARGV.size == 0
+			STDERR.puts "What do you want to do?"
+			STDERR.puts "usage:   select [options] filters"
+			STDERR.puts "example: cat *.json | select -j '.size >= 100'"
+			exit 1
+		end
+
+		# 1.1 get rules and stuff.
+		intent = ARGV[0]
+
+		case intent
+
+		# String comparison.
+		when /(?<attribute>[^ ]+)[ ]*(?<comparison>(eq|neq|=~)+)[ ]*(?<value>[^ ]+)/
+			attribute = $~["attribute"]
+			comparison = $~["comparison"]
+			value = $~["value"]
+			pp! "string comparison", attribute, comparison, value
+
+		# Numerical comparison.
+		when /(?<attribute>[^ ]+)[ ]*(?<comparison>[=<>]+)[ ]*(?<value>[^ ]+)/
+			attribute = $~["attribute"]
+			comparison = $~["comparison"]
+			value = $~["value"]
+			pp! "numerical comparison", attribute, comparison, value
+		else
+			STDERR.puts "cannot understand the intent of #{intent}"
+			exit 1
+		end
+
+		# TODO: FIXME
+		exit 0
+
+		buffer = Bytes.new 1_000_000 # 1 MB
+		decoder = CBOR::Decoder.new(buffer)
+
+		# 2. Get all input.
+		data = if Context.is_json
+			JSON.parse STDIN.gets_to_end
+		else
+			exit 0 if STDIN.read(buffer) == 0
+			v = decoder.read_value
+			exit 0 if v == 0 # FIXME: this is likely an error in the CBOR library.
+			v
+		end
+
+		# 2. TODO: oselect manipulations
+		result = if data.is_a?(JSON::Any)
+			data.to_json.to_slice
+		elsif data.is_a?(CBOR::Any)
+			data.to_cbor
+		else
+			STDERR.puts "data is neither JSON::Any or CBOR::Any"
+			exit 1
+		end
+
+		STDOUT.write result
+		STDOUT.flush
+	end
+end
+
+SelectApplication.new.run