interfaces: refactor

interfaces/05-log-parser/refactor-notes/refactor-00/changes.md

@@ -0,0 +1,34 @@
+## CHANGES
+
+### PROBLEM
++ adding new fields makes the code complex
++ needs to update: `result`, `parser`, `summarizer`
++ needs to add new fields to `parser`: `totalVisits` + `totalUniques`
++ in `parse()`: repeating line errors
+  + if we parsing out of it we'd need to have *parser — superfluous
+
+### SOLUTION
++ move all the result related logic to result.go
+
++ move `parser.go/result` -> `result.go`
+  + move `parser.go/parsing` logic -> `result.go`
+
++ add `addResult` -> `result.go`
+  + remove `parser struct`'s: `totalVisits`, `totalUniques`
+  + change `update()`'s last line: `p.sum[r.domain] = addResult`
+
++ remove `(line #d)` errors from `result.go`
+  + add: `return r, err` — named params are error prone
+  + always check for the error first
+    + `if r.visits < 0 || err != nil` -> `if err != nil || r.visits < 0`
+
++ `parser.go`: check the `parseFields()`:
+    ```golang
+    r, err := parseFields(line)
+    if err != nil {
+        p.lerr = fmt.Errorf("line %d: %v", p.lines, err)
+    }```
+
++ - `parser.go` and `summarize.go`
+  - remove `total int`
+  - let `summarize()` calculate the totals