[osh-language] Start getting rid of int_coerce for assoc array keys.

Instead we will use EvalWordToString, and disallow arbitrary
expressions.

Related to #207.

- Also add comments about assoc array literals
- All spec tests pass.  Tightened up spec for (( array1 == array 2 )).

osh/expr_eval.py

@@ -103,6 +103,7 @@ def _StringToInteger(s, span_id=const.NO_INTEGER):
 #
 # Calls EvalLhs()
 #   a[$key]=$val                 # osh/cmd_exec.py:814  (command_e.Assignment)
+# Calls _EvalLhsArith()
 #   (( a[key] = val ))           # osh/expr_eval.py:326 (_EvalLhsArith)
 #
 # Calls EvalLhsAndLookup():
@@ -369,16 +370,33 @@ def _Store(self, lval, new_int):
     val = value.Str(str(new_int))
     self.mem.SetVar(lval, val, (), scope_e.Dynamic)
 
-  def EvalToIndex(self, node):
-    # TODO:
-    # - For StrArray, Check that you got an integer (not None, etc.)
-    # - For AssocArray, do something else?  Get rid of int_coerce?
-    pass
+  def EvalWordToString(self, node):
+    """
+    Args:
+      node: arith_expr_t
+
+    Returns:
+      str
+
+    Raises:
+      util.FatalRuntimeError if the expression isn't a string
+      Or if it contains a bare variable like a[x]
+
+    These are allowed because they're unambiguous, unlike a[x]
+
+    a[$x] a["$x"] a["x"] a['x']
+    """
+    if node.tag != arith_expr_e.ArithWord:  # $(( $x )) $(( ${x}${y} )), etc.
+      # TODO: location info for orginal
+      e_die("Associative array keys must be strings: $x 'x' \"$x\" etc.")
+
+    val = self.word_ev.EvalWordToString(node.w)
+    return val.s
 
   def Eval(self, node, int_coerce=True):
     """
     Args:
-      node: osh_ast.arith_expr
+      node: arith_expr_t
 
     Returns:
       None for Undef  (e.g. empty cell)  TODO: Don't return 0!

osh/word_eval.py

@@ -662,7 +662,7 @@ def _EvalBracedVarSub(self, part, part_vals, quoted):
             val = value.Str(s)
 
         elif val.tag == value_e.AssocArray:
-          key = self.arith_ev.Eval(anode, int_coerce=False)
+          key = self.arith_ev.EvalWordToString(anode)
           s = val.d.get(key)
 
           if s is None:

osh/word_parse.py

@@ -963,6 +963,23 @@ def ReadForExpression(self):
 
   def _ReadArrayLiteralPart(self):
     # type: () -> word_part__ArrayLiteralPart
+    """
+    a=(1 2 3)
+
+    TODO: See osh/cmd_parse.py:164 for Id.Lit_ArrayLhsOpen, for a[x++]=1
+
+    We want:
+
+    A=(['x']=1 ["x"]=2 [$x$y]=3)
+
+    Maybe allow this as a literal string?  Because I think I've seen it before?
+    Or maybe force people to patch to learn the rule.
+
+    A=([x]=4)
+
+    Starts with Lit_Other '[', and then it has Lit_ArrayLhsClose
+    Maybe enforce that ALL have keys or NONE of have keys.
+    """
     self._Next(lex_mode_e.ShCommand)  # advance past (
     self._Peek()
     if self.cur_token.id != Id.Op_LParen:

spec/assoc.test.sh

@@ -244,11 +244,12 @@ assoc[i]=string
 assoc[i+1]=string+1
 ## END
 
-#### Array stored in associative array gets converted to string
+#### Array stored in associative array gets converted to string (without strict-array)
+
 array=('1 2' 3)
 declare -A d
-d[a]="${array[@]}"
-argv.py "${d[a]}"
+d['key']="${array[@]}"
+argv.py "${d['key']}"
 ## stdout: ['1 2 3']
 
 #### Indexed array as key of associative array coerces to string (without shopt -s strict-array)

spec/dbracket.test.sh

@@ -208,7 +208,7 @@ true
 false
 ## END
 
-#### (( array1 == array2 ))
+#### (( array1 == array2 )) doesn't work
 a=('1 3' 5)
 b=('1 3' 5)
 c=('1' '3 5')
@@ -224,18 +224,14 @@ echo status=$?
 (( a == d ))
 echo status=$?
 
-## STDOUT:
-status=0
-status=1
-status=1
-## END
-## N-I bash STDOUT:
+## stdout-json: ""
+## status: 1
+## BUG bash STDOUT:
 status=1
 status=1
 status=1
 ## END
-## N-I mksh stdout-json: ""
-## N-I mksh status: 1
+## BUG bash status: 0
 
 #### Quotes don't matter in comparison
 [[ '3' = 3 ]] && echo true

test/spec.sh

@@ -593,7 +593,7 @@ dbracket() {
 }
 
 dparen() {
-  sh-spec spec/dparen.test.sh --osh-failures-allowed 5 \
+  sh-spec spec/dparen.test.sh --osh-failures-allowed 4 \
     $BASH $MKSH $ZSH $OSH_LIST "$@"
 }