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feat: Allow expressions to be terminated/sequenced by ;

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Note that ultimately a terminated sequence may have
   a slightly different semantics (applying streams
   to `_|_`, most likely) but for now they don't.
This commit is contained in:
Glen Whitney 2021-02-10 12:47:34 -08:00
parent 991976d3a8
commit b9c8532899
10 changed files with 156 additions and 65 deletions
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6
bin/extract_tests.xsh
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@ -23,8 +23,10 @@ for path in TEST_LIST:
tests = re.split(r'test\s*(.+?)\s*\[\[.*?\n', contents)[1:]
testit = iter(tests)
for name, details in zip(testit, testit):
pfm = re.search(r'\n\s*\]\].*?parse\s*fails', details)
if pfm: continue # skip examples that don't parse
pfm = re.search(r'\n\s*\]\][\s\S]*?parse\s*fails', details)
if pfm: continue # skip examples that don't parse
ntfm = re.search(r'\n\s*\]\].*?don.t.test', details)
if ntfm: continue # explicit skip
em = re.search(r'\n\s*\]\]', details)
if not em: continue
example = details[:em.start()+1]

1
editor/Syntax.esv
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@ -20,6 +20,7 @@ menus
action: "Format" = editor-format (source)
action: "Show parsed AST" = debug-show-aterm (source)
action: "Desugar AST" = debug-desugar-fostr (source)
views

22
syntax/fostr.sdf3
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@ -10,16 +10,24 @@ context-free start-symbols
context-free sorts
Start LineSeq Line Ex
Start LineSeq Line OptTermEx TermExLst TermEx Ex
context-free syntax
Start.TopLevel = LineSeq
LineSeq = <<ln:Ex>> {layout(offside ln)}
LineSeq.Sequence = sq:Ex+ {layout(align-list sq)}
LineSeq = Line
LineSeq.Sequence = sq:Line+ {layout(align-list sq)}
Ex+ = Ex+ ln:Ex {layout(offside ln)}
Line = OptTermEx
Line.ISequence = TermExLst OptTermEx {layout(0.first.line == 1.first.line)}
TermExLst.Prior = TermEx+
OptTermEx = ex:Ex {layout(offside ex)}
OptTermEx = te:TermEx {layout(offside te)}
TermEx.Terminate = <<Ex>;>
Ex.Int = INT
Ex.Stream = <stream>
@ -36,8 +44,4 @@ context-free priorities
> Ex.Gets,
// prevent cycle: no singletons
LineSeq.Sequence <0> .> Ex+ = Ex,
// flat: No LineSeq immediately in LineSeq
Ex+ = Ex <0> .> LineSeq.Sequence,
Ex+ = Ex+ Ex <1> .> LineSeq.Sequence
LineSeq.Sequence <0> .> Line+ = Line

90
tests/basic.spt
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@ -14,8 +14,8 @@ that writes the sum of the ASCII codes for 'H', 'W', and '!' to standard output:
/** md */ test emit_sum [[
stream << 72 + 87 + 33
]]/* **/ parse to TopLevel(Gets(Stream(),
Sum(Sum(Int("72"), Int("87")), Int("33"))))
]] /* **/
parse to TopLevel(Gets(Stream(), Sum(Sum(Int("72"), Int("87")), Int("33"))))
/** writes
192**/
@ -59,7 +59,8 @@ is also left-associative, so that way we can chain insertions into a stream:
/** md */ test emit_twice [[
stream << 72 + 87 + 33 << 291
]]/* **/ parse to TopLevel(
]] /* **/
parse to TopLevel(
Gets(Gets(Stream(), Sum(Sum(Int("72"), Int("87")), Int("33"))), Int("291")))
/** writes
192291**/
@ -76,7 +77,8 @@ with `>>`; both forms return the first argument, so the following writes "824":
/** md */ test enters_twice [[
(7 + 8 >> stream + 9) >> stream
]]/* **/ parse to TopLevel(
]] /* **/
parse to TopLevel(
To(Sum(Sum(Int("7"), To(Int("8"), Stream())), Int("9")), Stream()))
/** writes
824**/
@ -96,7 +98,8 @@ stream <<
7
+ 8 >> stream
+ 9
]]/* **/ parse to TopLevel(
]] /* **/
parse to TopLevel(
Gets(Stream(), Sum(Sum(Int("7"), To(Int("8"), Stream())), Int("9"))))
/** writes
824**/
@ -107,15 +110,17 @@ stream <<
```fostr
**/
/** md */ test enter_receive_bad_break [[
/** md */ test enter_receive_bad_continuation [[
(7 + 8 >> stream + 9)
>> (stream << 9 + 2)
]] /* **/ parse fails
]] /* **/
parse fails
/* Extra tests not in the tour */
test enter_receive [[
(7 + 8 >> stream + 9) >> (stream << 9 + 2)
]]/* **/ parse to TopLevel(
]] /* **/
parse to TopLevel(
To(Sum(Sum(Int("7"),To(Int("8"),Stream())),Int("9")),
Gets(Stream(),Sum(Int("9"),Int("2")))))
/** writes
@ -135,18 +140,20 @@ lines are evaluated in sequence. For example, the program
+ 96
99 + 12 >>
stream
]] /* **/ parse to TopLevel( Sequence(
[ Gets(Stream(), Sum(Int("72"), Int("87")))
, Gets(Stream(), Sum(Int("88"), Int("96")))
, Sum(Int("99"), To(Int("12"), Stream()))]))
]] /* **/
parse to TopLevel(Sequence([
Gets(Stream(), Sum(Int("72"), Int("87"))),
Gets(Stream(), Sum(Int("88"), Int("96"))),
Sum(Int("99"), To(Int("12"), Stream()))
]))
/** writes
15918412**/
/** md
```
will write 15918412. fostr enforces that successive expressions in sequence
must line up at the left, i.e., the following will not parse:
will write 15918412. The fostr parser enforces that successive expressions
in sequence align at the left; e.g., the following fails to parse:
```fostr
**/
@ -156,8 +163,61 @@ must line up at the left, i.e., the following will not parse:
stream << 88
+ 96
99 + 12 >> stream
]] /* **/ parse fails
]] /* **/
parse fails
/** md
```
Note you can optionally terminate an expression in a sequence with a semicolon,
and you may place multiple expressions on a single line if the earlier one(s)
are so terminated. So the following is OK:
```fostr
**/
/** md */ test emit_several [[
stream << 1 + 2; 3 >> stream
(4 + 5) >> stream; stream << 6;
stream << 7
stream << 8
+ (9+10);
11 + 12 >> stream; 13 >> stream
>> stream
]] /* **/
parse to TopLevel(Sequence([
ISequence(Prior([Terminate(Gets(Stream(), Sum(Int("1"), Int("2"))))]),
To(Int("3"), Stream())),
ISequence(Prior([Terminate(To(Sum(Int("4"), Int("5")), Stream()))]),
Terminate(Gets(Stream(), Int("6")))),
Gets(Stream(), Int("7")),
Terminate(Gets(Stream(), Sum(Int("8"), Sum(Int("9"), Int("10"))))),
ISequence(Prior([Terminate(Sum(Int("11"), To(Int("12"), Stream())))]),
To(To(Int("13"), Stream()), Stream()))
]))
/** writes
3396727121313**/
/** md
```
**/
test emit_several_desugar [[
stream << 1 + 2; 3 >> stream
(4 + 5) >> stream; stream << 6;
stream << 7
stream << 8
+ (9+10);
11 + 12 >> stream; 13 >> stream
>> stream
]] /* don't test */
run desugar-fostr to TopLevel(Sequence([
Terminate(Gets(Stream(), Sum(Int("1"), Int("2")))),
To(Int("3"), Stream()),
Terminate(To(Sum(Int("4"), Int("5")), Stream())),
Terminate(Gets(Stream(), Int("6"))),
Gets(Stream(), Int("7")),
Terminate(Gets(Stream(), Sum(Int("8"), Sum(Int("9"), Int("10"))))),
Terminate(Sum(Int("11"), To(Int("12"), Stream()))),
To(To(Int("13"), Stream()), Stream())
]))

7
tests/emit_several.fos Normal file
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@ -0,0 +1,7 @@
stream << 1 + 2; 3 >> stream
(4 + 5) >> stream; stream << 6;
stream << 7
stream << 8
+ (9+10);
11 + 12 >> stream; 13 >> stream
>> stream

21
trans/analysis.str
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@ -9,6 +9,7 @@ imports
injections/-
libspoofax/term/origin
desugar
rules // Analysis
@ -19,7 +20,8 @@ rules // Analysis
// multi-file analysis
// editor-analyze = stx-editor-analyze(pre-analyze, post-analyze|"statics", "projectOk", "fileOk")
pre-analyze = origin-track-forced(explicate-injections-fostr-Start)
pre-analyze = desugar-fostr
; origin-track-forced(explicate-injections-fostr-Start)
post-analyze = origin-track-forced(implicate-injections-fostr-Start)
rules // Editor Services
@ -31,16 +33,21 @@ rules // Editor Services
rules // Debugging
// Prints the abstract syntax ATerm of a selection.
debug-show-aterm: (selected, _, _, path, project-path) -> (filename, result)
debug-show-aterm: (sel, _, _, path, projp) -> (filename, result)
with filename := <guarantee-extension(|"aterm")> path
; result := selected
; result := sel
// Prints the desugared abstract syntax ATerm of a selection.
debug-desugar-fostr: (sel, _, _, path, projp) -> (filename, result)
with filename := <guarantee-extension(|"desugared.aterm")> path
; result := <desugar-fostr> sel
// Prints the pre-analyzed abstract syntax ATerm of a selection.
debug-show-pre-analyzed: (selected, _, _, path, project-path) -> (filename, result)
debug-show-pre-analyzed: (sel, _, _, path, projp) -> (filename, result)
with filename := <guarantee-extension(|"pre-analyzed.aterm")> path
; result := <pre-analyze> selected
; result := <pre-analyze> sel
// Prints the analyzed annotated abstract syntax ATerm of a selection.
debug-show-analyzed: (selected, _, _, path, project-path) -> (filename, result)
debug-show-analyzed: (sel, _, _, path, projp) -> (filename, result)
with filename := <guarantee-extension(|"analyzed.aterm")> path
; result := selected
; result := sel

22
trans/desugar.str Normal file
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@ -0,0 +1,22 @@
module desugar
imports libstrategolib signatures/-
rules
/* ISequence() and Prior() are just noise for more expressions in sequence,
put in to get the layout rules right. So we remove them and collapse
all occurrence of them into one big Sequence() call on a list.
This is slightly tricky because there might not be any Sequence() call
at the top level, but yet an ISequence(). So we do it in two passes,
first converting ISequence()s to Sequence()s, and then collapsing
Sequence()s.
*/
deISe: ISequence(Prior(l),x) -> Sequence(<conc>(l, [x]))
enList: x -> [x]
seqFlatten: Sequence(l) -> Sequence(<mapconcat(?Sequence(<id>) <+ enList)>l)
strategies
desugar-fostr = bottomup(try(deISe <+ seqFlatten))

17
trans/haskell.str
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@ -1,10 +1,5 @@
module haskell
imports libstrategolib signatures/- util
signature
constructors
TopLevel: Ex -> Ex
rules
/* Approach: Generate code from the bottom up.
At every node, we create a pair of the implementation and
@ -25,20 +20,20 @@ rules
main = do
[p]return [c]]
hs: Stream() -> ("StdIO", "")
hs: Int(x) -> (x, "")
hs: Stream() -> ("StdIO", "")
hs: Int(x) -> (x, "")
hs: Sum( (c, p), (d, q)) -> ($[([c] + [d])], <conc-strings>(p,q))
hs: Gets((c, p), (d, q)) -> <hsget>(c,d,<conc-strings>(p,q),<newname>"fosgt")
hs: Gets((c, p), (d, q)) -> <hsget>(c,d,<conc-strings>(p,q),<newname>"fosgt")
hsget: (s, x, p, v) -> (v, <concat-strings>[p, $[[v] <- [s] `gets` [x]],
"\n"])
hs: To( (c, p), (d, q)) -> <hsto>(c,d,<conc-strings>(p,q),<newname>"fosto")
hsto: (x, s, p, v) -> (v, <concat-strings>[p, $[let [v] = [x]], "\n",
$[[s] `gets` [v]], "\n"])
$[[s] `gets` [v]], "\n"])
hs: Sequence(l) -> (<last; Fst>l, <map(Snd); concat-strings>l)
hs: Terminate((c,p)) -> ($[[c];;], p)
hs: Sequence(l) -> (<last; Fst>l, <map(Snd); concat-strings>l)
strategies

17
trans/javascript.str
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@ -1,10 +1,6 @@
module javascript
imports libstrategolib signatures/- util
signature
constructors
TopLevel: Ex -> Ex
rules
js: TopLevel(x) -> $[const Stdio = {
gets: v => { process.stdout.write(String(v)); return Stdio; },
@ -15,12 +11,13 @@ rules
}
[x]]
js: Stream() -> $[Stdio]
js: Int(x) -> x
js: Sum(x,y) -> $[[x] + [y]]
js: Gets(x, y) -> $[[x].gets([y])]
js: To(x, y) -> $[to([x],[y])]
js: Sequence(l) -> <join(|";\n")>l
js: Stream() -> $[Stdio]
js: Int(x) -> x
js: Sum(x,y) -> $[[x] + [y]]
js: Gets(x, y) -> $[[x].gets([y])]
js: To(x, y) -> $[to([x],[y])]
js: Terminate(x) -> x
js: Sequence(l) -> <join(|";\n")>l
strategies

18
trans/python.str
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@ -1,10 +1,5 @@
module python
imports libstrategolib signatures/- util
signature
constructors
TopLevel: Ex -> Ex
rules
py: TopLevel(x) -> $[import sys
@ -18,12 +13,13 @@ rules
Stdio = StdioC()
[x]]
py: Stream() -> $[Stdio]
py: Int(x) -> x
py: Sum(x,y) -> $[[x] + [y]]
py: Gets(x, y) -> $[[x].gets([y])]
py: To(x, y) -> $[to([x],[y])]
py: Sequence(l) -> <join(|"\n")>l
py: Stream() -> $[Stdio]
py: Int(x) -> x
py: Sum(x,y) -> $[[x] + [y]]
py: Gets(x, y) -> $[[x].gets([y])]
py: To(x, y) -> $[to([x],[y])]
py: Terminate(x) -> $[[x];]
py: Sequence(l) -> <join(|"\n")>l
strategies