Introduce {{<contents ...>}} in FDG chapter01 (#296)

Author: kloimhardt

src/mentat_collective/emmy/emmy_interactive.clj

@@ -63,7 +63,7 @@
      (->infix (simplify (down (first tuple) '= (second tuple))))))
 
 ^:kindly/hide-code
-(def tex (comp kind/tex emmy.expression.render/->TeX))
+(def tex str)
 
 ^:kindly/hide-code
 (def tex-simp (comp tex simplify))
@@ -139,3 +139,18 @@
                :on-click #(swap! *click-count inc)}]])])
 
 (show-tex "x^2")
+
+(kind/hiccup
+  [:div#target])
+
+(kind/scittle
+  '(let [source-div (.getElementById js/document "source")
+         target-div (.getElementById js/document "target")
+         clone-div (.cloneNode source-div true)]
+     (.appendChild target-div clone-div)))
+
+;;^{:kindly/kind :kind/hidden :kindly/hide-code true}
+
+(kind/hiccup
+  [:div {:id "source"}
+   [:p "test"]])

src/mentat_collective/emmy/fdg_ch01.clj

@@ -433,12 +433,13 @@
 (kind/hidden
   (define-coordinates t e/R1-rect))
 
-^:kindly/hide-code
-(def Cartan
+;; :::{#cartan}
+(define Cartan
   (Christoffel->Cartan
     (metric->Christoffel-2
       the-metric
       (coordinate-system->basis R2-rect))))
+;; :::
 
 (def geodesic-equation-residuals
   (((((covariant-derivative Cartan gamma) d:dt)
@@ -453,13 +454,7 @@
 
 ;;The Christoffel coefficients are computed from the metric:
 
-^:kindly/hide-code
-(kind/code
-  "(def Cartan
-    (Christoffel->Cartan
-      (metric->Christoffel-2
-        the-metric
-        (coordinate-system->basis R2-rect))))")
+;; {{<contents cartan>}}
 
 ;; The two messy residual results that we did not show are related by the metric.
 ;; If we change the representation of the geodesic equations by "lowering" them

src/mentat_collective/emmy/silcm_ch01.clj

@@ -16,12 +16,12 @@
             [mentat-collective.emmy.scheme :refer [define-1 let-scheme lambda]]
             [civitas.repl :as repl]))
 
-;; TODO: Make a button for @path-dimension to make dimensions switchable from 4 -> 2
-
 ;; I investigate a Lorentz covariant Lagrangian that is not widely known. It is discussed in the textbooks of Greiner, "Systems of Particles and Hamiltonian Mechanics" (chapter 21), and also [on-line in: Cline, "Variational Principles in Classical Mechanics"](https://phys.libretexts.org/Bookshelves/Classical_Mechanics/Variational_Principles_in_Classical_Mechanics_(Cline)/17%3A_Relativistic_Mechanics/17.06%3A_Lorentz-Invariant_Formulation_of_Lagrangian_Mechanics).
 
 ;; Then I derive, along deBroglie's argument, the momentum-wavelength relation of a free particle.
 
+#_"TODO: Make a button for @path-dimension to make dimensions switchable from 4 -> 2"
+
 ^:kindly/hide-code
 (def prod true) #_"used to check Emmy in Scittle kitchen"