Starting a re-write of the DSL, to be followed by the compiler.

Flip around field/table aliases, do joins a bit differently. They're my main
aims at the moment! I'll also add a preprocessor for the compiler to massage it
into a nicer form there.

I discovered that joins can be done with a pretty sweet syntax in SQL:

    (tableA LEFT JOIN tableB) RIGHT JOIN tableC

This is pretty much perfect for my purposes.

Flipping alias maps just makes more sense and removes a whole bunch of
`flip-map` calls that would be unnecessary if the aliases were the other way
around. The user-facing side of the DSL will be left unchanged, though. The
user provides an `{old-name new-name}` map and internally we convert that into
`{new-name old-name}`. Like magic.

I'm also adding a bunch more tests. Hopefully that will make things more likely
to work for long periods of time.

Peace out!

1 files changed, 14 insertions, 1 deletions

diff --git a/src/clojure_sql/util.clj b/src/clojure_sql/util.clj
index cd8e8b6..f2edf30 100644
--- a/src/clojure_sql/util.clj
+++ b/src/clojure_sql/util.clj
@@ -1,4 +1,5 @@
-(ns clojure-sql.util)
+(ns clojure-sql.util
+  (:require [clojure.set :as set]))
 
 (defn funcall [f & args]
   (apply f args))
@@ -11,3 +12,15 @@
   (->> m
        (map (comp vec reverse))
        (into {})))
+
+(defn map-kv [f & maps]
+  (let [all-keys (into #{} (mapcat keys maps))]
+    (->> all-keys
+         (map (fn [key]
+                (apply f key (map #(get % key) maps))))
+         (into {}))))
+
+(defn map-vals [f & maps]
+  (apply map-kv (fn [k & vs]
+                  [k (apply f vs)])
+         maps))