Implementing syntax parser (POSIX portability)

[magicant]

This is a tracking issue for implementation of the shell syntax parser.

Lexer items

• Operators
• Alias substitution
  • Normal aliases
  • Blank-ending aliases
• Redirections
  • Target file descriptors (IO_NUMBER) IO number parser #18
  • Single-word redirections (<, <>, >, >>, >|, <&, >&, >>|, <<<) Parsing normal redirections #12
  • Here documents (<<, <<-)
    • Quoted delimiters and literal here document contents Parse quoted delimiters and literal here document contents #24
    • Here document contents that contain escapes and expansions Parse escapes in here-document contents #23
    • Trimming leading tabs Remove leading tabs from <<- heredoc content #25
    • Refactoring here-doc content filling mechanism #131
• Word units
  • Backslashes
    • Escapes
    • Line continuations Handle line continuation in Lexer::peek_char #43
  • Single quotes Parse single quote syntax #21
  • Double quotes Parse double quote syntax #20
  • Tilde expansion Parsing tilde expansion syntax #29
  • Backquotes Parsing backquote syntax #31 Refactor backquote parser #46
  • Dollar units ($...)
    • Parameter expansion without braces ($FOO) Parsing raw parameter expansion #39
    • Parameter expansion with braces (${FOO})
      • Basic form (${foo}) Parsing braced parameter expansion (basic form) #40
      • Length modifier (${#foo}) Parsing length modifier for parameter expansion #42
      • Switch modifiers (${foo+bar}, ${foo-bar}, ${foo=bar}, ${foo?bar}, ${foo:+bar}, ${foo:-bar}, ${foo:=bar}, ${foo:?bar}) Parsing switch in braced parameter #44 Context-dependent parsing of switch word #45
      • Trim modifiers (${foo#bar}, ${foo##bar}, ${foo%bar}, ${foo%%bar}) Parse trim in braced parameter expansion #48
    • Command substitution ($(foo))
    • Arithmetic expansion ($((1+1))) Parsing arithmetic expansion #35

Parser items

• Lists (&, ;)
• And-or lists (&&, ||)
• Pipelines (|)
• Simple commands
  • Command words
  • Redirections
  • Assignments Parsing assignment #10 Parsing array assignment #11
• Compound commands
  • Braces ({ foo; }) Parsing grouping syntax #17
  • Subshells ((foo)) Parsing subshell syntax #13
  • For loops Parsing for loops #30
  • While and until loops Parsing while loop syntax #27 Parsinig until loop syntax #28
  • If conditional constructs Parsing if command #38
  • Case conditional constructs Parsing case conditional construct #34
• Function definitions
  • Without function keyword Parsing function definition command #14