Joseph Ferano
93231e8c9e
session.ml already had this: a compile-time walk over a Tast type that
emits the calls to print a value of it, handling every concrete type the
language has. It was dev-build-only and went to flan_dev_emit, and
prelude.ml justified the per-type print-* functions by saying a real
println had to wait for milestone 5 and generics. It did not. plan.org
specifies println as compiler-provided and per concrete type, which is
not overloading: there is nothing to dispatch on at run time and no
user-supplied printer to choose between, so no type variables appear.
The walk moves to render.ml, parameterised on an emitter and a slot
allocator. The emitter is five functions rather than five extern names
because the two sides are not both extern calls -- the REPL's are, and
stdout's compose a conversion with a write. The slot allocator differs
too: the REPL builds a thunk's frame, println takes slots from the
enclosing function being checked, once per call site.
Two runtime shims, both only reachable from the walk. flan_u64_to_bytes,
because routing u64 through the signed printer makes 0xFFFF...F read as
-1, which is the one way println could disagree with the REPL about a
value both can hold. flan_escape_bytes, so a string nested in a printed
structure is quoted and escaped -- same table as flan_dev_emit_str, noted
in both, because the REPL and println must not disagree about what a
struct looks like.
A string at top level prints raw and nested prints quoted. Not a conflict:
(println "hello") has to print hello, and a struct's string field has to
be distinguishable from the punctuation around it. The split is top-level
vs nested, so it lives in check.ml and not in the walk.
Found on the way: a field of an Option had no gep in emit.ml, so the
walk's Option arm had never run -- the REPL would have failed on one too.
Option is { i8, T } with no declared name, so its layout is now spelled
out. Nothing in the surface language reaches a field of an Option; the
printer does, to read the tag without unwrapping a None.
The print-* functions stay. They print without a newline, which println
cannot express -- slices.flan's show prints elements separated by spaces
-- and they are raw where print is structural.
println.flan covers every arm at -O0 and -O2: the u64, the raw/quoted
split, both Option arms, the depth and span caps, and the slice arm's
loop twice over plus once inside a dotimes, which is where per-call-site
slot allocation would show if it were per-iteration.
188 lines
8.4 KiB
EmacsLisp
188 lines
8.4 KiB
EmacsLisp
;;; flan-mode.el --- Major mode for Flan -*- lexical-binding: t; -*-
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;; Derived from lisp-mode, which is most of the work: Flan is s-expressions, so
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;; sexp motion, paren matching, `beginning-of-defun' and indentation all
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;; already do the right thing. What is left is what the language actually adds
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;; — its own literals and its own set of forms that indent like a body.
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;;; Code:
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(require 'lisp-mode)
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;; For `imenu-generic-expression', which is set below and which would
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;; otherwise be made buffer-local before its own defvar had run.
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(require 'imenu)
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;; The keymap binds them, but do not load the client merely to edit a file.
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;; These must be real autoloads, not just `declare-function`s: otherwise a
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;; user who has loaded only flan-mode cannot invoke M-x flan-dev at all.
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(autoload 'flan-eval-defun "flan-dev" nil t)
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(autoload 'flan-eval-buffer "flan-dev" nil t)
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(autoload 'flan-eval-last-sexp "flan-dev" nil t)
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(autoload 'flan-connect "flan-dev" nil t)
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(autoload 'flan-disconnect "flan-dev" nil t)
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(autoload 'flan-describe "flan-dev" nil t)
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(autoload 'flan-show-output "flan-dev" nil t)
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(autoload 'flan-repl "flan-repl" nil t)
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(autoload 'flan-break "flan-dev" nil t)
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;; The two CIDER-shaped buffers. They reach the daemon through an indirection
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;; of their own so that fixtures can drive them, so autoloading is all the
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;; wiring they need.
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(autoload 'flan-inspect "flan-inspect" nil t)
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(autoload 'flan-cnr-show "flan-cnr" nil t)
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(autoload 'flan-doc "flan-dev" nil t)
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(autoload 'flan-dev "flan-dev" nil t)
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(autoload 'flan-dev-quit "flan-dev" nil t)
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(autoload 'flan-dev-restart-program "flan-dev" nil t)
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(defgroup flan nil
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"Editing and evaluating Flan."
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:group 'languages
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:prefix "flan-")
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(defconst flan--definers
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'("defn" "defvar" "defconst" "defstruct" "defunion" "defenum" "defalias"
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"declare" "import" "package")
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"Forms that introduce a top-level name.")
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(defconst flan--special
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'("let" "if" "do" "while" "until" "dotimes" "loop" "match" "set" "return"
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"defer" "some" "none" "try" "zeroed" "uninit" "slice" "at" "len" "addr"
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"bytes" "cast" "true" "false" "nil" "print" "println")
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"Forms with meaning to the checker.")
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(defvar flan-font-lock-keywords
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`((,(concat "(" (regexp-opt flan--definers t) "\\_>"
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"[ \t]*\\(\\(?:\\sw\\|\\s_\\)+\\)?")
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(1 font-lock-keyword-face)
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(2 font-lock-function-name-face nil t))
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(,(concat "(" (regexp-opt flan--special t) "\\_>") 1 font-lock-keyword-face)
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;; A keyword resolves against an enum at the call site, so it reads as a
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;; constant rather than as a string.
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("\\_<:\\(?:\\sw\\|\\s_\\)+" . font-lock-constant-face)
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;; The machine types, which are ordinary symbols but never anything else.
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("\\_<\\(?:[iu]\\(?:8\\|16\\|32\\|64\\)\\|f\\(?:32\\|64\\)\\|bool\\|string\\|Unit\\|Never\\|Ptr\\|Option\\)\\_>"
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. font-lock-type-face)
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("\\_<\\(?:0x[0-9a-fA-F]+\\|-?[0-9]+\\(?:\\.[0-9]+\\)?\\)\\_>"
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. font-lock-constant-face))
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"Font lock for `flan-mode'.")
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(defconst flan--name-re "\\(\\(?:\\sw\\|\\s_\\)+\\)"
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"A Flan name, as one group.
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Written in terms of the syntax table rather than as a character class, so
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that the characters a name may contain are stated in one place — the table
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below — and not again here.")
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;; Anchored at the start of a line, which is where a top-level form is: a
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;; `defn' nested inside a `let' is not a definition of anything, and a match
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;; that ignored the column would offer one.
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(defvar flan-imenu-generic-expression
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`(("Functions" ,(concat "^(defn\\s-+" flan--name-re) 1)
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("Types" ,(concat "^(def\\(?:struct\\|union\\|enum\\|alias\\)\\s-+"
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flan--name-re)
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1)
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("Variables" ,(concat "^(def\\(?:var\\|const\\)\\s-+" flan--name-re) 1)
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;; A forward declaration is not a definition, and a file with both would
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;; otherwise show the same name twice with nothing to tell them apart.
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("Declared" ,(concat "^(declare\\s-+" flan--name-re) 1))
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"Imenu index for `flan-mode', by what each form introduces.")
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(defun flan-current-defun-name ()
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"The name of the top-level definition point is in, or nil.
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For `which-func-functions': a long file scrolled into the middle of a
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function is the case this exists for, and it is the case where the header
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line is off screen."
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(save-excursion
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(ignore-errors
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(beginning-of-defun)
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(and (looking-at (concat "(" (regexp-opt flan--definers t) "\\_>\\s-+"
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flan--name-re))
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(match-string-no-properties 2)))))
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(defvar flan-mode-syntax-table
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(let ((table (make-syntax-table lisp-mode-syntax-table)))
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;; Flan's own punctuation in names: a name may contain - ? > / and .
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(modify-syntax-entry ?? "_" table)
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(modify-syntax-entry ?! "_" table)
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(modify-syntax-entry ?/ "_" table)
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(modify-syntax-entry ?. "_" table)
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(modify-syntax-entry ?- "_" table)
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;; [ ] and { } are brackets, not symbol characters: every binding list and
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;; every type is written with them.
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(modify-syntax-entry ?\[ "(]" table)
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(modify-syntax-entry ?\] ")[" table)
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(modify-syntax-entry ?{ "(}" table)
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(modify-syntax-entry ?} "){" table)
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table)
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"Syntax table for `flan-mode'.")
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(defvar flan-mode-map
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(let ((map (make-sparse-keymap)))
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;; Autoloaded from flan-dev.el, so the client loads on first use.
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(define-key map (kbd "C-c C-c") #'flan-eval-defun)
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(define-key map (kbd "C-c C-k") #'flan-eval-buffer)
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(define-key map (kbd "C-x C-e") #'flan-eval-last-sexp)
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(define-key map (kbd "C-c C-z") #'flan-connect)
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(define-key map (kbd "C-c C-q") #'flan-disconnect)
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(define-key map (kbd "C-c C-d") #'flan-describe)
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(define-key map (kbd "C-c C-o") #'flan-show-output)
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(define-key map (kbd "C-c C-r") #'flan-repl)
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;; C-c C-b opens the buffer rather than the minibuffer prompt: it shows the
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;; same restarts plus the condition and the stack, and — the reason it
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;; replaces rather than joins — it is the one that refuses a *shadowed*
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;; restart instead of silently invoking a different frame's. flan-break is
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;; still there under C-c C-M-b for the one-key path.
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(define-key map (kbd "C-c C-b") #'flan-cnr-show)
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(define-key map (kbd "C-c C-M-b") #'flan-break)
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(define-key map (kbd "C-c C-i") #'flan-inspect)
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;; Help on the name at point. C-c C-d is taken by `flan-describe', which
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;; is about the session rather than about a name, and renaming a key that
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;; is already documented costs more than it is worth. Not C-c C-h either:
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;; C-h after a prefix is how anyone finds out what is under C-c, and a
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;; binding there takes that away.
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(define-key map (kbd "C-c C-v") #'flan-doc)
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;; The code the running program is calling for a name, as amd64 or as the
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;; IR it was built from. C-u for the IR rather than a second key: it is
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;; the same question asked of the same body.
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(define-key map (kbd "C-c C-a") #'flan-disassemble)
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;; The way out when a reload is refused: rebuild, relaunch, reconnect.
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(define-key map (kbd "C-c C-x") #'flan-dev-restart-program)
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map)
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"Keymap for `flan-mode'.")
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;;;###autoload
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(define-derived-mode flan-mode prog-mode "Flan"
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"Major mode for editing Flan.
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\\{flan-mode-map}"
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:syntax-table flan-mode-syntax-table
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(setq-local comment-start ";")
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(setq-local comment-start-skip ";+ *")
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(setq-local comment-add 1)
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(setq-local font-lock-defaults '(flan-font-lock-keywords))
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(setq-local indent-line-function #'lisp-indent-line)
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(setq-local lisp-indent-function #'flan-indent-function)
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(setq-local outline-regexp ";;;;+[ \t]*")
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(setq-local imenu-generic-expression flan-imenu-generic-expression)
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;; Buffer-locally, because this answers for Flan and nothing else.
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(add-hook 'which-func-functions #'flan-current-defun-name nil t))
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(defun flan-indent-function (indent-point state)
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"Indent like Lisp, with Flan's body forms as special forms.
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INDENT-POINT and STATE are as for `lisp-indent-function'."
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(let ((open (elt state 1)))
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(or (and open
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(save-excursion
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(goto-char (1+ open))
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(let ((head (and (looking-at "\\(\\sw\\|\\s_\\)+")
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(match-string 0))))
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(when (member head '("defn" "let" "if" "while" "until"
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"dotimes" "match" "do" "loop" "defer"))
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(+ (current-column) 1)))))
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(lisp-indent-function indent-point state))))
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;;;###autoload
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(add-to-list 'auto-mode-alist '("\\.flan\\'" . flan-mode))
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(provide 'flan-mode)
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;;; flan-mode.el ends here
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