fix off-by-one position problem of the goto codegen (#6) (#7)

src/codegen.jl

@@ -212,8 +212,6 @@ function generate_goto_code(machine::Machine, actions::Dict{Symbol,Expr}, check:
         if p > p_eof ≥ 0 && cs ∈ $(machine.final_states)
             $(eof_action_code)
             cs = 0
-        elseif cs < 0
-            p -= 1
         end
     end
 end

test/runtests.jl

@@ -715,6 +715,39 @@ module Test13
     @test validate(b"abrad") == ([], :error)
 end
 
+module Test14
+    import Automa
+    import Automa.RegExp: @re_str
+    const re = Automa.RegExp
+    using Base.Test
+
+    a = re"a*"
+    machine = Automa.compile(a)
+    @eval function validate_table(data)
+        $(Automa.generate_init_code(machine))
+        p_end = p_eof = sizeof(data)
+        $(Automa.generate_exec_code(machine, code=:table))
+        return p, cs
+    end
+    @eval function validate_inline(data)
+        $(Automa.generate_init_code(machine))
+        p_end = p_eof = sizeof(data)
+        $(Automa.generate_exec_code(machine, code=:inline))
+        return p, cs
+    end
+    @eval function validate_goto(data)
+        $(Automa.generate_init_code(machine))
+        p_end = p_eof = sizeof(data)
+        $(Automa.generate_exec_code(machine, code=:goto))
+        return p, cs
+    end
+
+    @test validate_table(b"")   == validate_inline(b"")   == validate_goto(b"")
+    @test validate_table(b"a")  == validate_inline(b"a")  == validate_goto(b"a")
+    @test validate_table(b"b")  == validate_inline(b"b")  == validate_goto(b"b")
+    @test validate_table(b"ab") == validate_inline(b"ab") == validate_goto(b"ab")
+end
+
 module TestDOT
     import Automa
     import Automa.RegExp: @re_str