=============================
Literal words
=============================

echo a
echo a b

---

(program
  (command (command_name (word)) (word))
  (command (command_name (word)) (word) (word)))

=============================
Words with special characters
=============================

echo {o[k]}
echo }}}
echo ]]] ===

---

(program
  (command (command_name (word)) (concatenation (word) (word)))
  (command (command_name (word)) (word))
  (command (command_name (word)) (word) (word)))

=============================
The regex operator
=============================

[[ "35d8b" =~ ^[0-9a-fA-F] ]]
[[ $CMD =~ (^|;)update_terminal_cwd($|;) ]]
[[ ! " ${completions[*]} " =~ " $alias_cmd " ]]

---

(program
  (bracket_command
    (string)
    (regex))
  (bracket_command
    (simple_expansion (variable_name))
    (regex))
  (bracket_command
    (word)
    (string (expansion (subscript (variable_name) (word))))
    (string (simple_expansion (variable_name)))))

=============================
Simple variable expansions
=============================

echo $abc

---

(program
  (command (command_name (word)) (simple_expansion (variable_name))))

=============================
Special variable expansions
=============================

echo $# $* $@

---

(program
  (command
    (command_name (word))
    (simple_expansion (special_variable_name))
    (simple_expansion (special_variable_name))
    (simple_expansion (special_variable_name))))

=============================
Variable expansions
=============================

echo ${abc}
echo ${abc:-def}
echo ${abc:- }
echo ${abc:
}

---

(program
  (command (command_name (word)) (expansion (variable_name)))
  (command (command_name (word)) (expansion (variable_name) (word)))
  (command (command_name (word)) (expansion (variable_name)))
  (command (command_name (word)) (expansion (variable_name))))

===================================
Variable expansions with operators
===================================

A="${B[0]# }"
C="${D/#* -E /}"
F="${G%% *}"

---

(program
  (variable_assignment
    (variable_name)
    (string (expansion (subscript (variable_name) (word)))))
  (variable_assignment
    (variable_name)
    (string (expansion (variable_name) (word) (word))))
  (variable_assignment
    (variable_name)
    (string (expansion (variable_name) (word) (word)))))

===================================
Variable expansions in strings
===================================

A="${A:-$B/c}"
A="${b/$c/$d}"

---

(program
  (variable_assignment
    (variable_name)
    (string
      (expansion
        (variable_name)
        (concatenation (simple_expansion (variable_name)) (word)))))
  (variable_assignment
    (variable_name)
    (string
      (expansion
        (variable_name)
        (concatenation
          (simple_expansion (variable_name))
          (word)
          (simple_expansion (variable_name)))))))

===================================
Other variable expansion operators
===================================

cat ${BAR} ${ABC=def} ${GHI:?jkl}

---

(program
  (command
    (command_name (word))
    (expansion (variable_name))
    (expansion (variable_name) (word))
    (expansion (variable_name) (word))))

=============================
Command substitutions
=============================

echo `echo hi`
echo $(echo $(echo hi))

---

(program
  (command
    (command_name (word))
    (command_substitution (command (command_name (word)) (word))))
  (command
    (command_name (word))
    (command_substitution (command
      (command_name (word))
      (command_substitution (command
        (command_name (word))
        (word)))))))

=============================
Process substitutions
=============================

wc -c <(echo abc && echo def)
echo abc > >(wc -c)

---

(program
  (command
    (command_name (word))
    (word)
    (process_substitution (list
      (command (command_name (word)) (word))
      (command (command_name (word)) (word)))))
  (command
    (command_name (word))
    (word)
    (file_redirect (process_substitution
      (command (command_name (word)) (word))))))

=============================
Single quoted strings
=============================

echo 'a b' 'c d'

---

(program
  (command (command_name (word)) (raw_string) (raw_string)))

=============================
Double quoted strings
=============================

echo "a" "b"
echo "a ${b} c" "d $e"

---

(program
  (command (command_name (word))
    (string)
    (string))
  (command (command_name (word))
    (string (expansion (variable_name)))
    (string (simple_expansion (variable_name)))))

=========================================
Strings containing command substitutions
=========================================

find "`dirname $file`" -name "$base"'*'

---

(program
  (command
    (command_name (word))
    (string (command_substitution (command (command_name (word)) (simple_expansion (variable_name)))))
    (word)
    (concatenation
      (string (simple_expansion (variable_name)))
      (raw_string))))

=========================================
Strings containing escape sequence
=========================================

echo "\"The great escape\`\${var}"

---

(program (command (command_name (word)) (string)))

=========================================
Variable declaration: declare & typeset
=========================================

declare var1
typeset -i -r var2=42 var3=10

---

(program
  (declaration_command (variable_name))
  (declaration_command (word) (word)
    (variable_assignment (variable_name) (word))
    (variable_assignment (variable_name) (word))))

=========================================
Variable declaration: readonly
=========================================

readonly var1
readonly var2=42

---

(program
  (declaration_command (variable_name))
  (declaration_command (variable_assignment (variable_name) (word))))

=========================================
Variable declaration: local
=========================================

local a=42 b
local -r c

---

(program
  (declaration_command
    (variable_assignment (variable_name) (word))
    (variable_name))
  (declaration_command
    (word)
    (variable_name)))

=========================================
Variable declaration: export
=========================================

export PATH
export FOOBAR PATH="$PATH:/usr/foobar/bin"

---

(program
  (declaration_command (variable_name))
  (declaration_command
    (variable_name)
    (variable_assignment (variable_name) (string (simple_expansion (variable_name))))))

===========================================
Expressions passed to declaration commands
===========================================

export "$(echo ${key} | tr [:lower:] [:upper:])=${p_key#*=}"

---

(program
  (declaration_command
    (string
      (command_substitution
        (pipeline
          (command (command_name (word)) (expansion (variable_name)))
          (command (command_name (word)) (concatenation (word)) (concatenation (word)))))
      (expansion (variable_name) (word)))))

=========================================
Arrays and array expansions
=========================================

a=()
b=(1 2 3)

echo ${a[@]}
echo ${#b[@]}

a[$i]=50
a+=(foo "bar" $(baz))

---

(program
  (variable_assignment (variable_name) (array))
  (variable_assignment (variable_name) (array (word) (word) (word)))
  (command (command_name (word)) (expansion (subscript (variable_name) (word))))
  (command (command_name (word)) (expansion (subscript (variable_name) (word))))
  (variable_assignment
    (subscript (variable_name) (simple_expansion (variable_name)))
    (word))
  (variable_assignment
    (variable_name)
    (array
      (word)
      (string)
      (command_substitution (command (command_name (word)))))))