Release 0.9.5

Major Feature Upgrade

• Better R7RS conformance
• New modules and procedures
• Added srfi supports
• More pleasant interactive experience
• Other notable improvements
• Changes that may alter the behavior of existing code
• Bug fixes

Better R7RS conformance

• Keyword-symbol integration: Gauche keywords (e.g. :key) can be symbols that are automatically bound to itself. It breaks the backward compatibility in some corner cases, however, so we haven't make the change in effect by default in 0.9.5. Setting the environment variable GAUCHE_KEYWORD_IS_SYMBOL turns on this feature. See Keywords, for the details. We urge you to test your code with this feature turned on, for pretty soon (probably in the next release) we'll make this feature effective by default.
• R7RS raise is now conformant of R7RS (which is slightly different from Gauche's builtin raise, which is srfi-18 conformant).

New modules and procedures

• Renamed modules (old names are still valid, but new code should use the new names):
  • Data structure implementations are now named data.*; so util.queue, util.sparse, util.trie are renamed to data.queue, data.sparse, data.trie.
  • Module text.unicode is renamed to gauche.unicode, for it's essential for R7RS support.
• New modules:
  • data.cache - Cache
  • data.heap - Heap
  • data.ring-buffer - Ring buffer
  • data.imap - Immutable map
  • data.ideque - Immutable deque
  • text.console: Simple console control module, works on both vt100-ish terminals and Windows console. Try examples/snake.scm to see it in action.
  • util.dominator - Find a dominator tree of a directed graph.
  • util.levenshtein - Calculate various edit-dinstances.
  • util.unification - Unification algorithm.
• Low-level hygienic macro support by er-macro-transformer.
• New builtin macros and procedures:
  • and-let1.
  • macroexpand-all - Expands everything in the given form.
  • sys-available-processors - query # of processor cores at runtime.
  • symbol-append.
  • sys-getgroups, sys-mkdtemp.
  • debug-label - Get unique label of an object.
  • length<?, length>?, length>=?, length=? - We had length<=?, so why not?
  • encode-float, inverse of decode-float.
• In gauche.uvector:
  • New procedures:string->u32vector!, string->s32vector!, make-uvector, port->uvector
  • Generic accessor and mutator uvector-ref, uvector-set!.
• In gauche.sequence:
  • New searching procedures - sequence-contains, break-list-by-sequence, break-list-by-sequence!, sequence->kmp-stepper.
  • New utilities - common-prefix, common-prefix-io.
• In gauche.array: Add constructors u8array, etc., for the consistency.
• In gauche.lazy: lappend-map
• In gauche.generator: gflatten, uvector->generator.
• In gauche.process:
  • run-process-pipeline - for easier pipelining.
  • shell-tokenize-string.
• In gauche.termios: sys-termios-copy
• In gauche.test:
  • test-none-of - As an expected value.
  • test-script - To test script files.
• In gauche.vport: List ports are added. See open-input-char-list, open-input-byte-list.
• In data.queue: mtqueue-num-waiting-readers.
• In data.trie: trie-longest-match.
• In data.random: samples$, for random sampling.
• In text.csv: Middle-layer procedures: csv-rows->tuples, make-csv-header-parser, make-csv-record-parser.
• In rfc.uri: uri-ref to access components of uri conveniently.
• In rfc.http: http-status-code->description.

Added srfi supports

• srfi-69: Basic hash tables
• srfi-111: Boxes
• srfi-112: Environment inquiry
• srfi-113: Sets and Bags
• srfi-114: Comparators
• srfi-117: Mutable queues
• srfi-118: Simple adjustable-size strings
• srfi-121: Generators - Covered by gauche.generator.
• srfi-128: Comparators (reduced) - the comparator is actually built-in to Gauche's core, so that other built-in mechanism such as hashtables, treemaps, sort, etc. can take comparators.
• srfi-131: ERR5RS Record Syntax (reduced) - Subset of gauche.record.
• srfi-133: Vector library
• srfi-134: Immutable deques - Covered by data.ideque.

More pleasant interactive experience

• Better error message while loading/compiling, using <mixin-condition> mechanism. Details.
• Improved describe.
• Toplevel REPL commands. See blog entry, or see the manual section "Working in REPL"
• Scheme-defined procedures maintain source code and source location. It can be queried by source-code and source-location. The source location is also shown by describe. (Source code isn't kept for precompiled Scheme code for now.)
• Online REPL document (info procedure, or ,info/,doc toplevel command) now shows just the named entry.
• Experimental support of line-editing. If the environment variable GAUCHE_READ_EDIT is set and the terminal is capable, you can use line editing (with emacs-like key binding). This feature still in early development stage and has number of known issues---especially, multiline edit only partially work. If you're brave, give it a shot, but don't blame me if your REPL explodes.
• You can invoke editor from repl by (ed file-or-procedure) (see ed). If the source location is known, you can directly jump to the source of the procedure, edit, and reload it.
• Now REPL consumes the trailing newline of input S-expr; that is, when you type (read-line) on REPL, it waits for your input. Before, REPL didn't consume the trailing newline, so (read-line) immediately returned when it sees the newline character left in the input buffer, but that confused users.
• use, select-module, export, import - Now these forms evaluate to zero values instead of #<undef>, for less cluttering of REPL.

Other notable improvements

• gauche.configure: More feature tests on compilers and linking. Start using package.scm for the source of package metainformation.
• Extended number syntax:
  • You can insert _ in prefixed numeric literal for readability, e.g. #b1101_1000_0001_1101.
  • Polar notation of numeric literal recognize pi suffix, e.g. 2@0.5pi => 0.0+2.0i.
  • The reader recognizes CL-ish #<radix>r syntax, e.g. #3r121 for 121 on base 3 (which is 16 in decimal).
• Hashtables are now salted, meaning, it uses different hash functions at least for each invocation of the program, so that it is immune to the hash collision attack. The hash function is deprecated, replaced by default-hash, portable-hash and legacy-hash. See the manual entry for the details.
• sys-sleep, sys-nanosleep: Changed to retry sleep/nanosleep by default if it is interrupted by as signal.
• A new debug special reader macro: #?,, which can be used as #?,(proc arg ...). When evaluated, it displays the form (proc arg ...) and each value of arg, then calls proc with those arguments and displays the return value(s). Similar to #?= but you can also check the actual value of arguments. The #?= stub is also improved to show the thread from which it is displaying.
• gauche.vport: open-output-uvector now takes an option to make the output buffer extendable.
• load searches .sld suffix as well, as some other R7RS implementations do.
• Stack trace now works for threads (but you have to call report-error within guard clauses explicitly, for by default unhandled error is propagated to the thread that calls thread-join!).
• gauche.uvector: s8vector->string and u8vector->string now take optional 'terminator' argument, convenient to extract NUL-terminated string from fixed size buffer.
• gauche.net: More flexible port number selection in make-server-socket and make-server-sockets.
• data.sparse: Allow default value per vector (a sparse vector returns its default value when unset element is accessed).
• rfc.http: Handles ipv6-style server address spec, e.g. [::1]:8888.
• file.util: copy-file - Now takes :if-exists and :append keyword arguments.
• crypt.bcrypt: Update bcrypt implementation and changed the default from 2a to 2b.
• gauche.termios: Support mintty on MSYS.
• rfc.tls: Add basic server-side certificate support.

Changes that may alter the behavior of existing code

• gauche.generator: gtake - changed optional argument spec to match srfi-121. Existing code that needs the old behavior can use a new procedure gtake*.
• If a hygienic macro inserts a fresh toplevel identifier, that identifier is renamed. E.g. if you say

  (define-syntax define-x (syntax-rules () ((_) (define x #t))))
  

  and then

  (define-x)
  

  the toplevel x is renamed and can't be referred to from outside. This is not explicitly specified in R7RS, but renaming is consistent with hygiene.
• U+180e Mongolian Vowel Separator is no longer treated as a whitespace character, since Unicode 6.3.0 changed its category from Zs to Cf.
• when, unless - Now they require at least one expr in their body.
• require: Now loads a file into a special module, instead of #<module gauche>. This may catch an error that was previously ignored. See the manual entry for the details.
• include, include-ci: Now relative pathnames, including ones that begin with ./ or ../, are taken relative to the includer file. Before, files beginning with ./ and ../ are treated specially, just like load. But it is less useful for include and just increases confusion.

Bug fixes

• Fixed numerous bugs in hygienic macro expander.
• When a module exports an inherited binding from renaming, it wasn't searched properly.
• util.match: Fixed a bug that doesn't handle match expressions generated by hygienic macros.
• Make -fcase-fold option affect REPL as well.
• fixnum-width: It returned a number one smaller than the correct value.
• Fixed a number reader bug handling very big or very small exponent.
• srfi-13: Fixed a bug in xsubstring when 'from' argument is negative.
• parameterize: Fixed a bug that failed to restore parameter values in some edge cases.