[spec/assoc] Cases for "cell sublanguage" and assoc arrays.

- unset -v
- declare -n
- ${!ref}

Not done: print -v

Addresses issue #651.

Unrelated: add some ideas in stdlib/README.md

spec/assoc.test.sh

@@ -470,3 +470,82 @@ len=1
 unset len=0
 ## END
 
+#### unset -v and assoc array
+show-len() {
+  echo len=${#A[@]}
+}
+
+declare -A A=(['K']=val)
+show-len
+
+unset -v 'A["K"]'
+show-len
+
+declare -A A=(['K']=val)
+show-len
+key=K
+unset -v 'A[$key]'
+show-len
+
+## STDOUT:
+len=1
+len=0
+len=1
+len=0
+## END
+
+#### nameref and assoc array
+show-values() {
+  echo values: ${A[@]}
+}
+
+declare -A A=(['K']=val)
+show-values
+
+declare -n ref='A["K"]'
+echo before $ref
+ref='val2'
+echo after $ref
+show-values
+
+echo ---
+
+key=K
+declare -n ref='A[$key]'
+echo before $ref
+ref='val3'
+echo after $ref
+show-values
+
+## STDOUT:
+values: val
+before val
+after val2
+values: val2
+---
+before val2
+after val3
+values: val3
+## END
+
+#### ${!ref} and assoc array
+show-values() {
+  echo values: ${A[@]}
+}
+
+declare -A A=(['K']=val)
+show-values
+
+declare ref='A["K"]'
+echo ref ${!ref}
+
+key=K
+declare ref='A[$key]'
+echo ref ${!ref}
+
+## STDOUT:
+values: val
+ref val
+ref val
+## END
+

stdlib/README.md

@@ -0,0 +1,19 @@
+stdlib/
+=======
+
+Ideas for shell functions that could be in here:
+
+- Version comparison: https://github.com/oilshell/oil/issues/683
+- An automated way to download the latest version of Oil: https://github.com/oilshell/oil/issues/463
+  - Maybe functions to lazily download documentation too?
+- `errexit` utilities: https://github.com/oilshell/oil/issues/474
+
+Already have:
+
+- `log` and `die`
+
+Note: The file `oil-polyfill.sh` is POSIX shell for functions that should be
+portable, e.g. like updating Oil, which may be done from the system shell.
+
+Other functions can be written in Oil.
+

test/spec.sh

@@ -658,7 +658,7 @@ append() {
 
 # associative array -- mksh and zsh implement different associative arrays.
 assoc() {
-  sh-spec spec/assoc.test.sh --osh-failures-allowed 1 \
+  sh-spec spec/assoc.test.sh --osh-failures-allowed 4 \
     $BASH $OSH_LIST "$@"
 }