Implement a basic version of declare/typeset -f / -F / -p.

- If any of these three flags are detected, then the statement is parsed
  like a builtin rather than an assignment.
- declare and typeset have identical behavior, like they do in bash.
  mksh doesn't implement 'declare'.

Addresses issue #59.

core/builtin.py

@@ -66,6 +66,7 @@
COLON
TEST BRACKET GETOPTS
COMMAND TYPE HELP
DECLARE TYPESET
""".split())


@@ -213,6 +214,11 @@ def Resolve(argv0):
  elif argv0 == "type":
    return EBuiltin.TYPE

  elif argv0 == "declare":
    return EBuiltin.DECLARE
  elif argv0 == "typeset":
    return EBuiltin.TYPESET

  elif argv0 == "help":
    return EBuiltin.HELP

@@ -970,6 +976,47 @@ def Type(argv, funcs, path_val):
  return status


DECLARE_SPEC = _Register('declare')
DECLARE_SPEC.ShortFlag('-f')
DECLARE_SPEC.ShortFlag('-F')
DECLARE_SPEC.ShortFlag('-p')


def DeclareTypeset(argv, mem, funcs):
  arg, i = DECLARE_SPEC.Parse(argv)

  status = 0

  # NOTE: in bash, -f shows the function body, while -F shows the name.  In
  # osh, they're identical and behave like -F.

  if arg.f or arg.F:  # Lookup and print functions.
    for name in argv[i:]:
      if name in funcs:
        print(name)
        # TODO: Could print LST, or render LST.  Bash does this.
        #print(funcs[name])
      else:
        status = 1

  elif arg.p:  # Lookup and print variables.

    for name in argv[i:]:
      val = mem.GetVar(name)
      if val.tag != value_e.Undef:
        # TODO: Print flags.
        print(name)
      else:
        status = 1

  else:
    raise NotImplementedError

  sys.stdout.flush()
  return status



def Trap(argv, traps):
  # TODO: register trap

core/cmd_exec.py

@@ -341,6 +341,10 @@ def _RunBuiltin(self, builtin_id, argv):
      path = self.mem.GetVar('PATH')
      status = builtin.Type(argv, self.funcs, path)

    elif builtin_id in (EBuiltin.DECLARE, EBuiltin.TYPESET):
      # These are synonyms
      status = builtin.DeclareTypeset(argv, self.mem, self.funcs)

    elif builtin_id == EBuiltin.HELP:
      loader = util.GetResourceLoader()
      status = builtin.Help(argv, loader)
@@ -505,7 +509,6 @@ def _RunSimpleCommand(self, argv, fork_external):
    if not argv:
      return 0  # status 0, or skip it?

    # TODO: respect the special builtin order too
    arg0 = argv[0]

    builtin_id = builtin.ResolveSpecial(arg0)

core/expr_eval.py

@@ -136,7 +136,7 @@ def _LookupVar(name, mem, exec_opts):
  return val


def EvalLhs(node, arith_ev, mem, exec_opts):
def _EvalLhs(node, arith_ev, mem, exec_opts):
  """Evaluate the operand for a++ a[0]++ as an R-value.

  Args:
@@ -225,7 +225,7 @@ def _EvalLhsToArith(self, node):
    Returns:
      int or list of strings, runtime.lvalue
    """
    val, lval = EvalLhs(node, self, self.mem, self.exec_opts)
    val, lval = _EvalLhs(node, self, self.mem, self.exec_opts)
    #log('Evaluating node %r -> %r', node, val)
    return self._ValToArithOrError(val), lval

osh/cmd_parse.py

@@ -457,6 +457,7 @@ def _MakeAssignment(self, assign_kw, suffix_words):
      # Maybe we could change this.
      #(Id.Assign_Export, '-p'),
  ])
  # Flags to parse like assignments: -a -r -x (and maybe -i)

  def ParseSimpleCommand(self):
    """

spec/assign.test.sh

@@ -192,3 +192,101 @@ argv.py "${a[@]}"
# stdout: ['x', 'z']
# N-I dash stdout-json: ""
# N-I dash status: 2

### declare -f 
func2=x  # var names are NOT found
declare -f myfunc func2
echo $?

myfunc() { echo myfunc; }
# This prints the source code.
declare -f myfunc func2 > /dev/null
echo $?

func2() { echo func2; }
declare -f myfunc func2 > /dev/null
echo $?
## STDOUT:
1
1
0
## END
## N-I dash/mksh STDOUT:
127
127
127
## END

### declare -p 
var1() { echo func; }  # function names are NOT found.
declare -p var1 var2 >/dev/null
echo $?

var1=x
declare -p var1 var2 >/dev/null
echo $?

var2=y
declare -p var1 var2 >/dev/null
echo $?
## STDOUT:
1
1
0
## N-I dash/mksh STDOUT:
127
127
127
## END

### typeset -f 
# mksh implement typeset but not declare
typeset  -f myfunc func2
echo $?

myfunc() { echo myfunc; }
# This prints the source code.
typeset  -f myfunc func2 > /dev/null
echo $?

func2() { echo func2; }
typeset  -f myfunc func2 > /dev/null
echo $?
## STDOUT:
1
1
0
## END
## N-I dash STDOUT:
127
127
127
## END

### typeset -p 
var1() { echo func; }  # function names are NOT found.
typeset -p var1 var2 >/dev/null
echo $?

var1=x
typeset -p var1 var2 >/dev/null
echo $?

var2=y
typeset -p var1 var2 >/dev/null
echo $?
## STDOUT:
1
1
0
## BUG mksh STDOUT:
# mksh doesn't respect exit codes
0
0
0
## END
## N-I dash STDOUT:
127
127
127
## END