fall back on shell command behaviour for undefined variables

Signed-off-by: Ava Hahn <ava@sunnypup.io>

Shell.org

@@ -170,3 +170,27 @@ Or:
 
 (pacman-search "xfce4")
 #+END_EXAMPLE
+
+* Implicit Load
+Typically, any call to an undefined function, lambda, or symbol will result in an undefined symbol error. For example, here is a call to GCC without explicitly prepending the ~load~ function:
+#+BEGIN_EXAMPLE
+  > (gcc myfile.c -o myfile)
+
+  ** ERROR TRACEBACK
+   > gdb: (is an undefined symbol)
+  Please refactor forms and try again...
+#+END_EXAMPLE
+
+With the ~implicit load~ feature any call to an undefined function will trigger the ~load~ function as if it had been there the whole time. The above example would yield a new subprocess running GCC (assuming it is installed and accessible). This allows users to quickly type shell commands at the prompt as if they were using a standard shell. Any reference to an undefined symbol outside of where a function would be will still cause an error.
+
+#+BEGIN_EXAMPLE
+  > ls -la .config
+
+  ...... (redacted directory list) .....
+#+END_EXAMPLE
+
+Implicit load can be used by building relish with the following command:
+
+#+BEGIN_EXAMPLE
+cargo build -F implicit-load
+#+END_EXAMPLE