[osh2oil] Clean up translation of assignments.

- Add more failing tests for complex assignments
- Add test for C literals

test/osh2oil.sh

@@ -483,9 +483,39 @@ f() { foo=bar spam=${var:-default}; }
OSH
proc f { setglobal foo = 'bar', spam = $(var or 'default'); }
OIL

}

assign-with-flags() {
  osh0-oil3 << 'OSH' 3<< 'OIL'
declare -r foo=bar
OSH
const foo = 'bar'
OIL

  osh0-oil3 << 'OSH' 3<< 'OIL'
declare -x foo=bar
OSH
export var foo = 'bar'
OIL

  osh0-oil3 << 'OSH' 3<< 'OIL'
declare -rx foo
declare -r -x foo
OSH
export const foo
export const foo
OIL

  osh0-oil3 << 'OSH' 3<< 'OIL'
f() {
  local -r foo=bar
}
OSH
proc f {
  const foo = 'bar'
}
OIL
}

array-literal() {
  osh0-oil3 << 'OSH' 3<< 'OIL'
@@ -966,6 +996,25 @@ echo \
OIL
}

# Hm I still don't have a syntax for this.  I don't like $'' because it's
# confusing with a var.  Use some other punctuation charater like %?
# @'' and @"" ?  &''  &"" ?
#
# Or get rid of word joining?   'foo'"'" becomes c'foo\''
# Glob/*.py/
# C'foo'
# List [1, 2, 'hi']  # JSON
#
# Yeah maybe capital C is better.

c-literal() {
  osh0-oil3 << 'OSH' 3<< 'OIL'
echo $'\tline\n'
OSH
echo c'\tline\n'
OIL
}

words() {
  # I probably should drive this with specific cases, rather than making it
  # super general.  Most scripts don't use WordPart juxtaposition.
@@ -986,6 +1035,14 @@ echo "$HOME/name with spaces"
OIL
}

word-joining() {
  osh0-oil3 << 'OSH' 3<< 'OIL'
echo 'foo'"'" 
OSH
echo c'foo\''
OIL
}

time-block() {
  osh0-oil3 << 'OSH' 3<< 'OIL'
time ls

tools/osh2oil.py

@@ -341,10 +341,8 @@ def DoAssignment(self, node, at_top_level, local_symbols):
    # Oil keywords:
    # - global : scope qualifier
    # - var, const : mutability
    # - setconst, export : state mutation
    #
    # Operators:
    # = and :=
    # - export : state mutation
    # - setconst -- make a variable mutable.  or maybe freeze var?
    #
    # NOTE: Bash also has "unset".  Does anyone use it?
    # You can use "delete" like Python I guess.  It's not the opposite of
@@ -357,9 +355,6 @@ def DoAssignment(self, node, at_top_level, local_symbols):
    # files are in the program.
    defined_locally = False  # is it a local variable in this function?
                             # can't tell if global
    # We can change it from = to := or ::= (in pedantic mode)
    new_assign_op_e = None

    if node.keyword == Id.Assign_Local:
      # Assume that 'local' it's a declaration.  In osh, it's an error if
      # locals are redefined.  In bash, it's OK to do 'local f=1; local f=2'.
@@ -402,8 +397,9 @@ def DoAssignment(self, node, at_top_level, local_symbols):
        self.f.write('set ')
        #self.f.write('[local mutated]')
      else:
        # we're in a function, but it's not defined locally.
        self.f.write('setglobal ')  # assume mutation of local
        # We're in a function, but it's not defined locally, so we must be
        # mutatting a global.
        self.f.write('setglobal ')

    elif node.keyword == Id.Assign_Readonly:
      # Explicit const.  Assume it can't be redefined.
@@ -421,6 +417,8 @@ def DoAssignment(self, node, at_top_level, local_symbols):
        self.cursor.SkipUntil(keyword_spid + 1)
        self.f.write('const')
      elif defined_locally:
        # TODO: Actually we might want 'freeze here.  In bash, you can make a
        # variable readonly after its defined.
        raise RuntimeError("Constant redefined locally")
      else:
        # Same as global level
@@ -451,11 +449,7 @@ def DoAssignment(self, node, at_top_level, local_symbols):

      # Replace name.  I guess it's Lit_Chars.
      self.f.write(pair.lhs.name)
      op = new_assign_op_e if new_assign_op_e else '='
      self.f.write(' %s ' % op)

      # foo=bar -> foo = 'bar'
      #print('RHS', pair.rhs, file=sys.stderr)
      self.f.write(' = ')

      # TODO: This should be translated from EmptyWord.
      if pair.rhs is None: