hello Jay what is Sexp Front? regards, Damien On Mon, Jun 19, 2023 at 3:53 AM Jay Sulzberger <j...@panix.com> wrote:
> > On Sun, 18 Jun 2023, Damien Mattei <damien.mat...@gmail.com> wrote: > > > hello, > > > > i'm porting the Python slicing ( > > https://docs.python.org/2/reference/expressions.html#slicings ) to > Scheme > > Guile and Racket. > > > > examples in Scheme+ : > > > > {#(1 2 3 4 5 6 7)[2 / 5]} > > #(3 4 5) > > Damien, thank you for your work in this! > > Guile will be stronger when it get a serious standard array-slice > library. > > For myself I would rather use > > (slice #(1 2 3 4 5 6 7) '(from/to 2 5)) > > I admit that I am a member, in mostly good standing, of the Sexp Front. > > I deny the ridiculous accusation that the Front falls under the ban on > oath-bound societies. Almost all our gatherings are open to the > public. At such open meetings, all are welcome . I hope that you and > I may meet and sit down together at such a gathering. The few > meetings that are closed are for internal business. > > Again, thank you! > > I remain, as ever, your fellow student of history and probability, > Jay Sulzberger > > > > > > i'm using / instead of : because : is already used by the SRFI 42 Eager > > Comprehension > > > > below are my testing examples: > > > > ;;; compiled > > > /Users/mattei/.cache/guile/ccache/3.0-LE-8-4.6/usr/local/share/guile/site/3.0/Scheme+.scm.go > > > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8)[/ / 3]} > > $1 = #(1 4 7) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8)[/ / -2]} > > $2 = #(8 6 4 2) > > scheme@(guile-user)> {"elephant"[2 / 5]} > > $3 = "eph" > > scheme@(guile-user)> {"abcdefghijkl"[/ / -3]} > > $4 = "lifc" > > scheme@(guile-user)> {"123456789"[ / / -1]} > > $5 = "987654321" > > scheme@(guile-user)> {"abcdefghijkl"[/ / 2]} > > $6 = "acegik" > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[/ 7 / 2]} > > $7 = #(1 3 5 7) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[/ 6 / -1]} > > $8 = #(6 5 4 3 2 1) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[/ 6 / -2]} > > $9 = #(6 4 2) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[/ -3 / -2]} > > $10 = #(6 4 2) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[3 / / 2]} > > $11 = #(4 6 8) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[3 / / -2]} > > $12 = #(4 2) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[-3 / / 2]} > > $13 = #(7 9) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[-3 / / -2]} > > $14 = #(7 5 3 1) > > scheme@(guile-user)> {"123456789"[/ -3 / -2]} > > $15 = "642" > > scheme@(guile-user)> {"abcdefghijklmno"[/ 7 / 2]} > > $16 = "aceg" > > scheme@(guile-user)> {"123456789"[/ -3 / -2]} > > $17 = "642" > > scheme@(guile-user)> {"abcdefghijklmno"[3 / / 2]} > > $18 = "dfhjln" > > scheme@(guile-user)> {"123456789"[3 / / 2]} > > $19 = "468" > > scheme@(guile-user)> {"123456789"[3 / / -2]} > > $20 = "42" > > scheme@(guile-user)> {"123456789"[-3 / / -2]} > > $21 = "7531" > > scheme@(guile-user)> {"123456789"[-3 / / 2]} > > $22 = "79" > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[2 / 5 / 1]} > > $23 = #(3 4 5) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[5 / 2 / -1]} > > $24 = #(6 5 4) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[2 / 5 / -1]} > > $25 = #() > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[-1 / 5 / -1]} > > $26 = #(9 8 7) > > scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[-0 / 5 / -1]} > > $27 = #() > > scheme@(guile-user)> {"0123456789"[5 / 2 / -1]} > > $28 = "543" > > scheme@(guile-user)> {"0123456789"[5 / / -1]} > > $29 = "543210" > > scheme@(guile-user)> {"0123456789"[5 / 0 / -1]} > > $30 = "54321" > > > > the syntax is derived from Python syntax: > > > > [1,2,3,4,5,6,7,8,9][-3::2] > > [7, 9] > > [1,2,3,4,5,6,7,8,9][-3::-2] > > [7, 5, 3, 1] > > [1,2,3,4,5,6,7,8,9][3::-2] > > [4, 2] > > "abcdefghijkl"[: : -3] > > 'lifc' > > [1,2,3,4,5,6,7,8,9][:5:-1] > > [9, 8, 7] > > [1,2,3,4,5,6,7,8,9][:5:1] > > [1, 2, 3, 4, 5] > > [1,2,3,4,5,6,7,8,9][0:5:-1] > > [] > > [1,2,3,4,5,6,7,8,9][-0:5:-1] > > [] > > [1,2,3,4,5,6,7,8,9][-1:5:-1] > > [9, 8, 7] > > [1,2,3,4,5,6,7,8,9][:5:-1] > > [9, 8, 7] > > [1,2,3,4,5,6,7,8,9][10:5:-1] > > [9, 8, 7] > > [1,2,3,4,5,6,7,8,9][2:5:-1] > > [] > > [1,2,3,4,5,6,7,8,9][5:2:-1] > > [6, 5, 4] > > [0,1,2,3,4,5,6,7,8,9][5:2:-1] > > [5, 4, 3] > > [0,1,2,3,4,5,6,7,8,9][5::-1] > > [5, 4, 3, 2, 1, 0] > > [0,1,2,3,4,5,6,7,8,9][5:0:-1] > > [5, 4, 3, 2, 1] > > > > for now it works in simple expressions,soon it will be implemented for > > expressions with LHS and RHS like {container1[2 / 5] <- container2[7 / > 9]} > > for this reason all will be in the next version of Scheme+ > > https://github.com/damien-mattei/Scheme-PLUS-for-Guile > > with other features too. > > > > Damien > > >
