AST parsing

closes #2

spec/ameba/rules/line_length_spec.cr

@@ -6,17 +6,17 @@ module Ameba::Rules
 
   describe LineLength do
     it "passes if all lines are shorter than 80 symbols" do
-      source = Source.new "", "short line"
+      source = Source.new "short line"
       subject.catch(source).valid?.should be_true
     end
 
     it "fails if there is at least one line longer than 79 symbols" do
-      source = Source.new "", long_line
+      source = Source.new long_line
       subject.catch(source).valid?.should be_false
     end
 
     it "reports rule, pos and message" do
-      source = Source.new "", long_line
+      source = Source.new long_line
       subject.catch(source).valid?.should be_false
 
       error = source.errors.first

spec/ameba/rules/trailing_blank_lines_spec.cr

@@ -5,27 +5,27 @@ module Ameba::Rules
 
   describe TrailingBlankLines do
     it "passes if there is no blank lines at the end" do
-      source = Source.new "", "no-blankline"
+      source = Source.new "no-blankline"
       subject.catch(source).valid?.should be_true
     end
 
     it "fails if there is a blank line at the end of a source" do
-      source = Source.new "", "a = 1\n \n "
+      source = Source.new "a = 1\n \n "
       subject.catch(source).valid?.should be_false
     end
 
     it "passes if source is empty" do
-      source = Source.new "", ""
+      source = Source.new ""
       subject.catch(source).valid?.should be_true
     end
 
     it "passes if last line is not blank" do
-      source = Source.new "", "\n\n\n puts 22"
+      source = Source.new "\n\n\n puts 22"
       subject.catch(source).valid?.should be_true
     end
 
     it "reports rule, pos and message" do
-      source = Source.new "", "a = 1\n\n "
+      source = Source.new "a = 1\n\n "
       subject.catch(source)
 
       error = source.errors.first

spec/ameba/rules/trailing_whitespace_spec.cr

@@ -5,17 +5,17 @@ module Ameba::Rules
 
   describe TrailingWhitespace do
     it "passes if all lines do not have trailing whitespace" do
-      source = Source.new "", "no-whispace"
+      source = Source.new "no-whispace"
       subject.catch(source).valid?.should be_true
     end
 
     it "fails if there is a line with trailing whitespace" do
-      source = Source.new "", "whitespace at the end "
+      source = Source.new "whitespace at the end "
       subject.catch(source).valid?.should be_false
     end
 
     it "reports rule, pos and message" do
-      source = Source.new "", "a = 1\n b = 2 "
+      source = Source.new "a = 1\n b = 2 "
       subject.catch(source).valid?.should be_false
 
       error = source.errors.first

spec/ameba/source_spec.cr

@@ -3,20 +3,17 @@ require "../spec_helper"
 module Ameba
   describe Source do
     describe ".new" do
-      it "allows to create a source by file path" do
-        Source.new(__FILE__).path.should eq __FILE__
-      end
-
       it "allows to create a source by content and path" do
-        s = Source.new(__FILE__, "content")
-        s.path.should eq __FILE__
-        s.lines.should eq %w(content)
+        s = Source.new("content", "path")
+        s.path.should eq "path"
+        s.content.should eq "content"
+        s.lines.should eq ["content"]
       end
     end
 
     describe "#error" do
       it "adds and error" do
-        s = Source.new(__FILE__)
+        s = Source.new ""
         s.error(DummyRule.new, 23, "Error!")
         s.errors.size.should eq 1
         s.errors.first.rule.should_not be_nil
@@ -24,5 +21,15 @@ module Ameba
         s.errors.first.message.should eq "Error!"
       end
     end
+
+    describe "#ast" do
+      it "returns ast nodes" do
+        s = Source.new %(
+          class A; end
+          class B; end
+        )
+        s.ast.to_s.should eq "class A\nend\nclass B\nend\n"
+      end
+    end
   end
 end

src/ameba.cr

@@ -13,7 +13,7 @@ module Ameba
   end
 
   def run(files, formatter : Formatter)
-    sources = files.map { |path| Source.new(path) }
+    sources = files.map { |path| Source.new(File.read path) }
 
     reporter = Reporter.new formatter
     reporter.start sources

src/ameba/rules/trailing_blank_lines.cr

@@ -1,7 +1,7 @@
 # A rule that disallows trailing blank lines at the end of the source file.
 
 Ameba.rule TrailingBlankLines do |source|
-  if source.lines.size > 1 && source.lines[-2, 2].join.strip == ""
+  if source.lines.size > 1 && source.lines[-2, 2].join.strip.empty?
     source.error self, source.lines.size,
       "Blank lines detected at the end of the file"
   end

src/ameba/source.cr

@@ -1,8 +1,9 @@
+require "compiler/crystal/syntax/*"
+
 module Ameba
   # An entity that represents a Crystal source file.
   # Has path, lines of code and errors reported by rules.
   class Source
-
     # Represents an error caught by Ameba.
     #
     # Each error has the rule that created this error,
@@ -14,14 +15,11 @@ module Ameba
 
     getter lines : Array(String)
     getter errors = [] of Error
-    getter path : String
+    getter path : String?
+    getter content : String
 
-    def initialize(@path : String)
-      @lines = File.read_lines(@path)
-    end
-
-    def initialize(@path : String, content : String)
-      @lines = content.split("\n")
+    def initialize(@content : String, @path = nil)
+      @lines = @content.split("\n")
     end
 
     def error(rule : Rule, line_number : Int32, message : String)
@@ -31,5 +29,9 @@ module Ameba
     def valid?
       errors.empty?
     end
+
+    def ast
+      Crystal::Parser.new(@content).tap { |p| p.filename = @path }.parse
+    end
   end
 end