tanaid

tuh-NAY-id

i am learning rust and tcl by writing a tcl interpreter. i chose tcl because it is "very simple" and actually used for some things.

implements a (probably broken) subset of tcl:

• syntax
  • bare words
  • $variable substitution
  • {braced words}
  • ${braced variable} substitution
  • [command args] substituion
  • "quoted strings"
  • "$variable and [command]" substitution in quoted strings
• builtin commands
  • break
  • continue
  • dict create ?key value ...?
  • dict get dictValue ?key ...?
  • dict exists dictValue key ?key ...?
  • dict set dictVariable key ?key ...? value
  • expr arg ?arg arg ...?
  • foreach varlist1 list1 ?varlist2 list2 ...? body
  • global ?varname ...?
  • if expr1 ?then? body1 elseif expr2 ?then? body2 elseif ... ?else? ?bodyN?
  • incr varName ?increment?
  • info exists varName
  • lappend listVar ?value value value ...?
  • lindex listVal index
  • list ?arg arg ...?
  • llength listVal
  • lreverse listVal
  • proc name args body
  • puts string
  • return ?result?
  • set varName ?value?
  • string index string charIndex
  • string length string
  • unknown cmdName ?arg arg ...?
  • uplevel ?level? arg ?arg ...?
  • upvar ?level? otherVar myVar ?otherVar myVar ...?
  • while test body

this is enough to write simple scripts like:

proc fib {x} {
  if {$x <= 0} {
    return 0
  }
  if {$x == 1} {
    return 1
  }
  return [expr {[fib [expr {$x - 1}]] + [fib [expr {$x - 2}]]}]
}

set i 1
while {$i < 30} {
  puts [fib $i]
  set i [expr {$i + 1}]
}

Usage

cargo build --release

# repl
./target/release/tanaid

# run a script
./target/release/tanaid path/to/file.tcl

Setup

Install Rust with rustup:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Run any Cargo command from the repo root to install/use the toolchain:

cargo build

Development

Run the compiler checks with:

cargo check --all-targets