spath3 (23jan21)

git-svn-id: svn://tug.org/texlive/trunk@57504 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 171 insertions, 150 deletions

diff --git a/Master/texmf-dist/tex/latex/spath3/tikzlibraryknots.code.tex b/Master/texmf-dist/tex/latex/spath3/tikzlibraryknots.code.tex
index 0322a679410..5872a71fdf3 100644
--- a/Master/texmf-dist/tex/latex/spath3/tikzlibraryknots.code.tex
+++ b/Master/texmf-dist/tex/latex/spath3/tikzlibraryknots.code.tex
@@ -4,17 +4,17 @@
 %%
 %% The original source files were:
 %%
-%% spath3.dtx  (with options: `knots')
+%% spath3_code.dtx  (with options: `knots')
 %% ----------------------------------------------------------------
 %% spath3 --- Functions for manipulating PGF soft paths
-%% E-mail: stacey@math.ntnu.no
+%% E-mail: loopspace@mathforge.org
 %% Released under the LaTeX Project Public License v1.3c or later
 %% See http://www.latex-project.org/lppl.txt
 %% ----------------------------------------------------------------
 %% 
 %%
 \RequirePackage{spath3}
-\usetikzlibrary{intersections}
+\usetikzlibrary{intersections,spath3}
 
 \ExplSyntaxOn
 
@@ -22,8 +22,6 @@
 \tl_new:N \l__knot_tmpb_tl
 \tl_new:N \l__knot_tmpc_tl
 \tl_new:N \l__knot_tmpd_tl
-\tl_new:N \l__knot_tmpe_tl
-\tl_new:N \l__knot_tmpf_tl
 \tl_new:N \l__knot_tmpg_tl
 \tl_new:N \l__knot_redraws_tl
 \tl_new:N \l__knot_clip_width_tl
@@ -31,16 +29,21 @@
 \tl_new:N \l__knot_node_tl
 \tl_new:N \l__knot_aux_tl
 \tl_new:N \l__knot_auxa_tl
+\tl_new:N \l__knot_prefix_tl
+
+\seq_new:N \l__knot_segments_seq
 
 \int_new:N \l__knot_tmpa_int
 \int_new:N \l__knot_strands_int
-\int_new:N \l__knot_intersections_int
-\int_new:N \l__knot_filaments_int
+\int_new:N \g__knot_intersections_int
+\int_new:N \g__knot_filaments_int
 \int_new:N \l__knot_component_start_int
 
+\fp_new:N \l__knot_tmpa_fp
+\fp_new:N \l__knot_tmpb_fp
+
 \dim_new:N \l__knot_tmpa_dim
 \dim_new:N \l__knot_tmpb_dim
-\dim_new:N \l__knot_tmpc_dim
 \dim_new:N \l__knot_tolerance_dim
 \dim_new:N \l__knot_clip_bg_radius_dim
 \dim_new:N \l__knot_clip_draw_radius_dim
@@ -56,10 +59,16 @@
 \bool_new:N \l__knot_skip_bool
 \bool_new:N \l__knot_save_bool
 
-\seq_new:N \l__knot_nodes_seq
+\seq_new:N \g__knot_nodes_seq
 
 \bool_set_true:N \l__knot_ignore_ends_bool
 \tikzset{
+  spath/prefix/knot/.style={
+    spath/set~ prefix=knot strand,
+  },
+  spath/suffix/knot/.style={
+    spath/set~ suffix={},
+  },
   knot/.code={
     \tl_if_eq:nnTF {#1} {none}
     {
@@ -218,7 +227,7 @@
   \int_incr:N \l__knot_strands_int
   \tl_clear_new:c {l__knot_options_strand \int_use:N \l__knot_strands_int}
   \tl_set:cn {l__knot_options_strand \int_use:N \l__knot_strands_int} {#1}
-  \path[#1,save~ spath=knot strand \int_use:N  \l__knot_strands_int]
+  \path[#1,spath/set~ name=knot,spath/save=\int_use:N \l__knot_strands_int]
 }
 \NewDocumentEnvironment{knot} { O{} }
 {
@@ -232,7 +241,7 @@
   \tikzset{knot~ diagram/.cd,every~ knot~ diagram/.try,#1}
   \int_zero:N \l__knot_strands_int
   \tl_clear:N \l__knot_redraws_tl
-  \seq_gclear:N \l__knot_nodes_seq
+  \seq_gclear:N \g__knot_nodes_seq
 }
 \cs_new_protected_nopar:Npn \knot_render:
 {
@@ -245,25 +254,23 @@
     \bool_if:NTF \l__knot_self_intersections_bool
     {
       \knot_split_strands:
-      \int_set_eq:NN \l__knot_tmpa_int \l__knot_filaments_int
+      \int_set_eq:NN \l__knot_tmpa_int \g__knot_filaments_int
       \tl_set:Nn \l__knot_prefix_tl {filament}
     }
     {
       \int_set_eq:NN \l__knot_tmpa_int \l__knot_strands_int
       \tl_set:Nn \l__knot_prefix_tl {strand}
     }
-    \int_gzero:N \l__knot_intersections_int
-    \bool_if:NTF \l__knot_draft_bool
+    \int_gzero:N \g__knot_intersections_int
+    \tl_clear:N \l__knot_node_tl
+    \bool_if:NT \l__knot_draft_bool
     {
       \tl_set:Nn \l__knot_node_tl {
         \exp_not:N \node[coordinate,
-          pin={[node~ contents={\int_use:N \l__knot_intersections_int},knot~ diagram/draft/crossing~ label, knot~ diagram/draft/crossing~ \int_use:N \l__knot_intersections_int \c_space_tl label/.try]
+          pin={[node~ contents={\int_use:N \g__knot_intersections_int},knot~ diagram/draft/crossing~ label, knot~ diagram/draft/crossing~ \int_use:N \g__knot_intersections_int \c_space_tl label/.try]
             }]
       }
     }
-    {
-      \tl_set:Nn \l__knot_node_tl {\exp_not:N \node[coordinate]}
-    }
     \int_step_variable:nnnNn {1} {1} {\l__knot_tmpa_int - 1} \l__knot_tmpa_tl
     {
       \int_step_variable:nnnNn {\tl_use:N \l__knot_tmpa_tl + 1} {1}     {\l__knot_tmpa_int} \l__knot_tmpb_tl
@@ -272,7 +279,7 @@
       }
     }
     \tl_use:N \l__knot_redraws_tl
-    \seq_use:Nn \l__knot_nodes_seq {}
+    \seq_use:Nn \g__knot_nodes_seq {}
   }
   \endpgfscope
 }
@@ -280,11 +287,11 @@
 {
   \pgfscope
   \group_begin:
-  \tl_set:Nn \l_tmpa_tl {knot~ diagram/every~ strand/.try,}
-  \tl_put_right:Nv \l_tmpa_tl {l__knot_options_strand #1}
-  \tl_put_right:Nn \l_tmpa_tl {,knot~ diagram/only~ when~ rendering/.try,only~ when~ rendering/.try}
-  \spath_bake_round:n {knot strand #1}
-  \spath_tikz_path:Vn \l_tmpa_tl {knot strand #1}
+  \spath_bake_round:c {knot strand #1}
+  \tl_set:Nn \l__knot_tmpa_tl {knot~ diagram/every~ strand/.try,}
+  \tl_put_right:Nv \l__knot_tmpa_tl {l__knot_options_strand #1}
+  \tl_put_right:Nn \l__knot_tmpa_tl {,knot~ diagram/only~ when~ rendering/.try,only~ when~ rendering/.try}
+  \spath_tikz_path:Vv \l__knot_tmpa_tl {knot strand #1}
   \group_end:
   \endpgfscope
 }
@@ -293,11 +300,11 @@
 {
   \bool_if:NT \l__knot_draft_bool
   {
-    \spath_get:nnN {knot strand #1} {final point} \l__knot_tmpb_tl
+    \spath_finalpoint:Nv \l__knot_tmpb_tl {knot strand #1}
     \dim_set:Nn \l__knot_tmpa_dim {\tl_item:Nn \l__knot_tmpb_tl {1}}
     \dim_set:Nn \l__knot_tmpb_dim {\tl_item:Nn \l__knot_tmpb_tl {2}}
     \node[knot~ diagram/draft/strand~label] at (\l__knot_tmpa_dim,\l__knot_tmpb_dim) {#1};
-    \spath_get:nnN {knot strand #1} {initial point} \l__knot_tmpb_tl
+    \spath_initialpoint:Nv \l__knot_tmpb_tl {knot strand #1}
     \dim_set:Nn \l__knot_tmpa_dim {\tl_item:Nn \l__knot_tmpb_tl {1}}
     \dim_set:Nn \l__knot_tmpb_dim {\tl_item:Nn \l__knot_tmpb_tl {2}}
     \node[knot~ diagram/draft/strand~label] at (\l__knot_tmpa_dim,\l__knot_tmpb_dim) {#1};
@@ -309,84 +316,86 @@
   }
   {
     \tl_clear:N \l__knot_tmpa_tl
-    \spath_map_segment_function:nN {knot strand #1} \knot_split_self_intersects:NN
-    \spath_put:nnV {knot strand #1} {path} \l__knot_tmpa_tl
+    \spath_segments_to_seq:Nv \l__knot_segments_seq {knot strand #1}
+    \seq_map_function:NN \l__knot_segments_seq \knot_split_self_intersects:N
+    \tl_set_eq:cN {knot strand #1} \l__knot_tmpa_tl
   }
 }
-\cs_new_protected_nopar:Npn \knot_split_self_intersects:NN #1#2
+\cs_new_protected_nopar:Npn \knot_split_self_intersects:N #1
 {
-  \tl_case:NnF #1
+  \tl_set:Nx \l__knot_tmpc_tl {\tl_item:nn {#1} {4}}
+  \tl_case:NnF \l__knot_tmpc_tl
   {
-    \g__spath_curvetoa_tl
+    \c_spath_curvetoa_tl
     {
-      \fp_set:Nn \l_tmpa_fp
+      \fp_set:Nn \l__knot_tmpa_fp
       {
-        (\tl_item:Nn #2 {3} - 3 * \tl_item:Nn #2 {6} + 3 * \tl_item:Nn #2 {9} - \tl_item:Nn #2 {12})
+        (\tl_item:nn {#1} {3} - 3 * \tl_item:nn {#1} {6} + 3 * \tl_item:nn {#1} {9} - \tl_item:nn {#1} {12})
         *
-        (3 * \tl_item:Nn #2 {8} - 3 * \tl_item:Nn #2 {11})
+        (3 * \tl_item:nn {#1} {8} - 3 * \tl_item:nn {#1} {11})
         -
-        (\tl_item:Nn #2 {2} - 3 * \tl_item:Nn #2 {5} + 3 * \tl_item:Nn #2 {8} - \tl_item:Nn #2 {11})
+        (\tl_item:nn {#1} {2} - 3 * \tl_item:nn {#1} {5} + 3 * \tl_item:nn {#1} {8} - \tl_item:nn {#1} {11})
         *
-        (3 * \tl_item:Nn #2 {9} - 3 * \tl_item:Nn #2 {12})
+        (3 * \tl_item:nn {#1} {9} - 3 * \tl_item:nn {#1} {12})
       }
-      \fp_set:Nn \l_tmpb_fp
+      \fp_set:Nn \l__knot_tmpb_fp
       {
-        (\tl_item:Nn #2 {2} - 3 * \tl_item:Nn #2 {5} + 3 * \tl_item:Nn #2 {8} - \tl_item:Nn #2 {11})
+        (\tl_item:nn {#1} {2} - 3 * \tl_item:nn {#1} {5} + 3 * \tl_item:nn {#1} {8} - \tl_item:nn {#1} {11})
         *
-        (3 * \tl_item:Nn #2 {6} - 6 * \tl_item:Nn #2 {9} + 3 * \tl_item:Nn #2 {12})
+        (3 * \tl_item:nn {#1} {6} - 6 * \tl_item:nn {#1} {9} + 3 * \tl_item:nn {#1} {12})
         -
-        (\tl_item:Nn #2 {3} - 3 * \tl_item:Nn #2 {6} + 3 * \tl_item:Nn #2 {9} - \tl_item:Nn #2 {12})
+        (\tl_item:nn {#1} {3} - 3 * \tl_item:nn {#1} {6} + 3 * \tl_item:nn {#1} {9} - \tl_item:nn {#1} {12})
         *
-        (3 * \tl_item:Nn #2 {5} - 6 * \tl_item:Nn #2 {8} + 3 * \tl_item:Nn #2 {11})
+        (3 * \tl_item:nn {#1} {5} - 6 * \tl_item:nn {#1} {8} + 3 * \tl_item:nn {#1} {11})
       }
       \fp_compare:nTF
       {
-        \l_tmpb_fp != 0
+        \l__knot_tmpb_fp != 0
       }
       {
-        \fp_set:Nn \l_tmpa_fp {.5 * \l_tmpa_fp / \l_tmpb_fp}
+        \fp_set:Nn \l__knot_tmpa_fp {.5 * \l__knot_tmpa_fp / \l__knot_tmpb_fp}
         \fp_compare:nTF
         {
-          0 < \l_tmpa_fp && \l_tmpa_fp < 1
+          0 < \l__knot_tmpa_fp && \l__knot_tmpa_fp < 1
         }
         {
-          \spath_split_curve:VVNN \l_tmpa_fp #2 \l_tmpa_tl \l_tmpb_tl
-          \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-          \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-          \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-          \tl_set:Nx \l_tmpb_tl {\tl_tail:N \l_tmpb_tl}
-          \tl_set:Nx \l_tmpb_tl {\tl_tail:N \l_tmpb_tl}
-          \tl_set:Nx \l_tmpb_tl {\tl_tail:N \l_tmpb_tl}
-          \tl_put_right:NV \l__knot_tmpa_tl \l_tmpa_tl
-          \tl_put_right:NV \l__knot_tmpa_tl \l_tmpb_tl
+          \spath_split_curve:NNnV \l__knot_tmpc_tl \l__knot_tmpd_tl {#1} \l__knot_tmpa_fp
+          \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+          \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+          \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+          \tl_set:Nx \l__knot_tmpd_tl {\tl_tail:N \l__knot_tmpd_tl}
+          \tl_set:Nx \l__knot_tmpd_tl {\tl_tail:N \l__knot_tmpd_tl}
+          \tl_set:Nx \l__knot_tmpd_tl {\tl_tail:N \l__knot_tmpd_tl}
+          \tl_put_right:NV \l__knot_tmpa_tl \l__knot_tmpc_tl
+          \tl_put_right:NV \l__knot_tmpa_tl \l__knot_tmpd_tl
         }
         {
-          \tl_set_eq:NN \l_tmpa_tl #2
-          \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-          \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-          \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-          \tl_put_right:NV \l__knot_tmpa_tl \l_tmpa_tl
+          \tl_set:Nn \l__knot_tmpc_tl {#1}
+          \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+          \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+          \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+          \tl_put_right:NV \l__knot_tmpa_tl \l__knot_tmpc_tl
         }
       }
       {
-        \tl_set_eq:NN \l_tmpa_tl #2
-        \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-        \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-        \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-        \tl_put_right:NV \l__knot_tmpa_tl \l_tmpa_tl
+        \tl_set:Nn \l__knot_tmpc_tl {#1}
+        \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+        \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+        \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+        \tl_put_right:NV \l__knot_tmpa_tl \l__knot_tmpc_tl
       }
     }
-    \g__spath_lineto_tl
+    \c_spath_lineto_tl
     {
-      \tl_set_eq:NN \l_tmpa_tl #2
-      \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-      \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-      \tl_set:Nx \l_tmpa_tl {\tl_tail:N \l_tmpa_tl}
-      \tl_put_right:NV \l__knot_tmpa_tl \l_tmpa_tl
+      \tl_set:Nn \l__knot_tmpc_tl {#1}
+      \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+      \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+      \tl_set:Nx \l__knot_tmpc_tl {\tl_tail:N \l__knot_tmpc_tl}
+      \tl_put_right:NV \l__knot_tmpa_tl \l__knot_tmpc_tl
     }
   }
   {
-    \tl_put_right:NV \l__knot_tmpa_tl #2
+    \tl_put_right:Nn \l__knot_tmpa_tl {#1}
   }
 }
 \cs_new_protected_nopar:Npn \knot_intersections:nn #1#2
@@ -396,8 +405,8 @@
   \tl_put_right:Nn \l__knot_tmpa_tl {#1}
   \tl_set_eq:NN \l__knot_tmpb_tl \l__knot_prefix_tl
   \tl_put_right:Nn \l__knot_tmpb_tl {#2}
-  \spath_get:nnN {knot \tl_use:N \l__knot_tmpa_tl} {path} \l__knot_tmpc_tl
-  \spath_get:nnN {knot \tl_use:N \l__knot_tmpb_tl} {path} \l__knot_tmpd_tl
+  \tl_set_eq:Nc \l__knot_tmpc_tl {knot \tl_use:N \l__knot_tmpa_tl}
+  \tl_set_eq:Nc \l__knot_tmpd_tl {knot \tl_use:N \l__knot_tmpb_tl}
 
   \bool_if:nTF {
     \l__knot_save_bool
@@ -411,10 +420,12 @@
 \pgfintersectionofpaths{\pgfsetpath\l__knot_tmpc_tl}{\pgfsetpath\l__knot_tmpd_tl}
 
   }
+
   \int_compare:nT {\pgfintersectionsolutions > 0}
   {
     \int_step_function:nnnN {1} {1} {\pgfintersectionsolutions} \knot_do_intersection:n
   }
+
   \knot_save_intersections:VV \l__knot_tmpa_tl \l__knot_tmpb_tl
   \group_end:
 }
@@ -464,10 +475,10 @@
   \bool_set_false:N \l__knot_skip_bool
   \bool_if:NT \l__knot_self_intersections_bool
   {
-    \tl_set:Nn \l_tmpa_tl {knot previous}
-    \tl_put_right:NV \l_tmpa_tl \l__knot_tmpa_tl
-    \tl_set:Nv \l_tmpa_tl \l_tmpa_tl
-    \tl_if_eq:NNT \l_tmpa_tl \l__knot_tmpb_tl
+    \tl_set:Nn \l__knot_tmpc_tl {knot previous}
+    \tl_put_right:NV \l__knot_tmpc_tl \l__knot_tmpa_tl
+    \tl_set:Nv \l__knot_tmpc_tl \l__knot_tmpc_tl
+    \tl_if_eq:NNT \l__knot_tmpc_tl \l__knot_tmpb_tl
     {
       \knot_test_endpoint:VnT \l__knot_tmpb_tl {final point}
       {
@@ -475,10 +486,10 @@
       }
     }
 
-    \tl_set:Nn \l_tmpa_tl {knot previous}
-    \tl_put_right:NV \l_tmpa_tl \l__knot_tmpb_tl
-    \tl_set:Nv \l_tmpa_tl \l_tmpa_tl
-    \tl_if_eq:NNT \l_tmpa_tl \l__knot_tmpa_tl
+    \tl_set:Nn \l__knot_tmpc_tl {knot previous}
+    \tl_put_right:NV \l__knot_tmpc_tl \l__knot_tmpb_tl
+    \tl_set:Nv \l__knot_tmpc_tl \l__knot_tmpc_tl
+    \tl_if_eq:NNT \l__knot_tmpc_tl \l__knot_tmpa_tl
     {
       \knot_test_endpoint:VnT \l__knot_tmpa_tl {final point}
       {
@@ -508,23 +519,23 @@
   \bool_if:NF \l__knot_skip_bool
   {
 
-    \int_gincr:N \l__knot_intersections_int
+    \int_gincr:N \g__knot_intersections_int
     \bool_if:nF
     {
       \tl_if_exist_p:c {l__knot_ignore_crossing_ \int_use:N
-        \l__knot_intersections_int}
+        \g__knot_intersections_int}
       &&
       ! \tl_if_empty_p:c {l__knot_ignore_crossing_ \int_use:N
-        \l__knot_intersections_int}
+        \g__knot_intersections_int}
     }
     {
       \bool_if:nTF
       {
         \tl_if_exist_p:c {l__knot_crossing_ \int_use:N
-          \l__knot_intersections_int}
+          \g__knot_intersections_int}
         &&
         ! \tl_if_empty_p:c {l__knot_crossing_ \int_use:N
-          \l__knot_intersections_int}
+          \g__knot_intersections_int}
       }
       {
         \tl_set_eq:NN \l__knot_tmpg_tl \l__knot_tmpb_tl
@@ -553,9 +564,10 @@
           \l__knot_prepend_prev_bool || \l__knot_append_next_bool
         }
         {
-          \spath_clone:nn {knot \tl_use:N \l__knot_tmpg_tl}
-          {knot \tl_use:N \l__knot_prefix_tl -1}
+          \tl_clear_new:c {knot \tl_use:N \l__knot_prefix_tl -1}
+          \tl_set_eq:cc {knot \tl_use:N \l__knot_prefix_tl -1} {knot \tl_use:N \l__knot_tmpg_tl}
 
+          \tl_clear_new:c {l__knot_options_ \tl_use:N \l__knot_prefix_tl -1}
           \tl_set_eq:cc {l__knot_options_ \tl_use:N \l__knot_prefix_tl -1} {l__knot_options_ \tl_use:N \l__knot_tmpg_tl}
 
           \bool_if:nT
@@ -567,7 +579,7 @@
             !\tl_if_empty_p:c {knot previous \tl_use:N \l__knot_tmpg_tl}
           }
           {
-            \spath_prepend_no_move:nn {knot \tl_use:N \l__knot_prefix_tl -1} {knot \tl_use:c {knot previous \tl_use:N \l__knot_tmpg_tl}}
+            \spath_prepend_no_move:cv {knot \tl_use:N \l__knot_prefix_tl -1} {knot \tl_use:c {knot previous \tl_use:N \l__knot_tmpg_tl}}
             \bool_if:nT
             {
               \l__knot_splits_bool
@@ -579,10 +591,9 @@
             {
               \knot_test_endpoint:vnT {knot previous \tl_use:N \l__knot_tmpg_tl} {initial point}
               {
-                \spath_get:nnN {knot \tl_use:N \l__knot_prefix_tl -1} {path} \l_tmpa_tl
-                \spath_prepend_no_move:nn {knot \tl_use:N \l__knot_prefix_tl -1} {knot \tl_use:c {knot previous \tl_use:c {knot previous \tl_use:N \l__knot_tmpg_tl}}}
-                \spath_get:nnN {knot \tl_use:N \l__knot_prefix_tl -1} {path} \l_tmpa_tl
 
+                \spath_prepend_no_move:cv {knot \tl_use:N \l__knot_prefix_tl -1} {knot \tl_use:c {knot previous \tl_use:c {knot previous \tl_use:N \l__knot_tmpg_tl}}}
+                \tl_set_eq:Nc \l__knot_tmpa_tl {knot \tl_use:N \l__knot_prefix_tl -1}
               }
             }
           }
@@ -595,7 +606,7 @@
             !\tl_if_empty_p:c {knot previous \tl_use:N \l__knot_tmpg_tl}
           }
           {
-            \spath_append_no_move:nn {knot \tl_use:N \l__knot_prefix_tl -1} {knot \tl_use:c {knot next \tl_use:N \l__knot_tmpg_tl}}
+            \spath_append_no_move:cv {knot \tl_use:N \l__knot_prefix_tl -1} {knot \tl_use:c {knot next \tl_use:N \l__knot_tmpg_tl}}
             \bool_if:nT
             {
               \l__knot_splits_bool
@@ -608,7 +619,7 @@
             {
               \knot_test_endpoint:vnT {knot previous \tl_use:N \l__knot_tmpg_tl} {final point}
               {
-                \spath_append_no_move:nn {knot \tl_use:N \l__knot_prefix_tl -1} {knot \tl_use:c {knot next \tl_use:c {knot next \tl_use:N \l__knot_tmpg_tl}}}
+                \spath_append_no_move:cv {knot \tl_use:N \l__knot_prefix_tl -1} {knot \tl_use:c {knot next \tl_use:c {knot next \tl_use:N \l__knot_tmpg_tl}}}
 
               }
             }
@@ -619,13 +630,16 @@
       }
       \pgfscope
       \group_begin:
-      \tikzset{knot~ diagram/every~ intersection/.try, every~ intersection/.try, knot~ diagram/intersection~ \int_use:N \l__knot_intersections_int/.try}
-      \knot_draw_crossing:nVV {\tl_use:N \l__knot_tmpg_tl} \l__knot_tmpa_dim \l__knot_tmpb_dim
+      \tikzset{knot~ diagram/every~ intersection/.try, every~ intersection/.try, knot~ diagram/intersection~ \int_use:N \g__knot_intersections_int/.try}
+      \knot_draw_crossing:VVV \l__knot_tmpg_tl \l__knot_tmpa_dim \l__knot_tmpb_dim
+      \coordinate (\l__knot_name_tl \c_space_tl \int_use:N \g__knot_intersections_int) at (\dim_use:N \l__knot_tmpa_dim, \dim_use:N \l__knot_tmpb_dim);
       \group_end:
       \endpgfscope
     }
-    \seq_gpush:Nx \l__knot_nodes_seq { \l__knot_node_tl (\l__knot_name_tl \c_space_tl \int_use:N \l__knot_intersections_int) at (\dim_use:N \l__knot_tmpa_dim, \dim_use:N \l__knot_tmpb_dim) {};}
-
+    \tl_if_empty:NF \l__knot_node_tl
+    {
+      \seq_gpush:Nx \g__knot_nodes_seq { \l__knot_node_tl at (\dim_use:N \l__knot_tmpa_dim, \dim_use:N \l__knot_tmpb_dim) {};}
+    }
   }
 }
 
@@ -649,7 +663,7 @@
 }
 \prg_new_protected_conditional:Npnn \knot_test_endpoint:nn #1#2 {T,F,TF}
 {
-  \spath_get:nnN {knot #1} {#2} \l__knot_tmpd_tl
+  \use:c {spath_#2:Nv} \l__knot_tmpd_tl {knot #1}
   \knot_test_endpoint:NTF \l__knot_tmpd_tl
   {
     \prg_return_true:
@@ -662,49 +676,49 @@
 \cs_generate_variant:Nn \knot_test_endpoint:nnT {VnT,vnT}
 \cs_generate_variant:Nn \knot_test_endpoint:nnF {VnF,vnF}
 \cs_generate_variant:Nn \knot_test_endpoint:nnTF {VnTF,vnTF}
-\cs_new_nopar:Npn \knot_draw_crossing:nnn #1#2#3
+\cs_new_protected_nopar:Npn \knot_draw_crossing:nnn #1#2#3
 {
   \group_begin:
   \pgfscope
   \path[knot~ diagram/background~ clip] (#2, #3) circle[radius=\l__knot_clip_bg_radius_dim];
 
-  \tl_set:Nn \l_tmpa_tl {knot~ diagram/every~ strand/.try,}
+  \tl_set:Nn \l__knot_tmpa_tl {knot~ diagram/every~ strand/.try,}
   \tl_if_exist:cT {l__knot_options_ #1}
   {
-  \tl_put_right:Nv \l_tmpa_tl {l__knot_options_ #1}
+  \tl_put_right:Nv \l__knot_tmpa_tl {l__knot_options_ #1}
   }
-  \tl_put_right:Nn \l_tmpa_tl {,knotbg,line~ width= \tl_use:N \l__knot_clip_width_tl * \pgflinewidth}
-  \spath_tikz_path:Vn \l_tmpa_tl {knot #1}
+  \tl_put_right:Nn \l__knot_tmpa_tl {,knotbg,line~ width= \tl_use:N \l__knot_clip_width_tl * \pgflinewidth}
+  \spath_tikz_path:Vv \l__knot_tmpa_tl {knot #1}
 
   \endpgfscope
 
   \pgfscope
   \path[knot~ diagram/clip] (#2, #3) circle[radius=\l__knot_clip_draw_radius_dim];
 
-  \tl_set:Nn \l_tmpa_tl {knot~ diagram/every~ strand/.try,}
+  \tl_set:Nn \l__knot_tmpa_tl {knot~ diagram/every~ strand/.try,}
   \tl_if_exist:cT {l__knot_options_ #1}
   {
-  \tl_put_right:Nv \l_tmpa_tl {l__knot_options_ #1}
+  \tl_put_right:Nv \l__knot_tmpa_tl {l__knot_options_ #1}
   }
-  \tl_put_right:Nn \l_tmpa_tl {,knot~ diagram/only~ when~ rendering/.try,only~ when~ rendering/.try}
-  \spath_tikz_path:Vn \l_tmpa_tl {knot #1}
+  \tl_put_right:Nn \l__knot_tmpa_tl {,knot~ diagram/only~ when~ rendering/.try,only~ when~ rendering/.try}
+  \spath_tikz_path:Vv \l__knot_tmpa_tl {knot #1}
 
   \endpgfscope
   \group_end:
 }
 
-\cs_generate_variant:Nn \knot_draw_crossing:nnn {nVV}
+\cs_generate_variant:Nn \knot_draw_crossing:nnn {nVV, VVV}
 
-\cs_new_nopar:Npn \knot_draw_crossing:nn #1#2
+\cs_new_protected_nopar:Npn \knot_draw_crossing:nn #1#2
 {
   \tikz@scan@one@point\pgfutil@firstofone #2 \relax
   \knot_draw_crossing:nVV {#1} \pgf@x \pgf@y
 }
 \cs_new_protected_nopar:Npn \knot_split_strands:
 {
-  \int_gzero:N \l__knot_filaments_int
+  \int_gzero:N \g__knot_filaments_int
   \int_step_function:nnnN {1} {1} {\l__knot_strands_int} \knot_split_strand:n
-  \int_step_function:nnnN {1} {1} {\l__knot_filaments_int} \knot_compute_nexts:n
+  \int_step_function:nnnN {1} {1} {\g__knot_filaments_int} \knot_compute_nexts:n
 }
 \cs_new_protected_nopar:Npn \knot_compute_nexts:n #1
 {
@@ -713,66 +727,70 @@
 }
 \cs_new_protected_nopar:Npn \knot_split_strand:n #1
 {
-  \int_set_eq:NN \l__knot_component_start_int \l__knot_filaments_int
+  \int_set_eq:NN \l__knot_component_start_int \g__knot_filaments_int
   \int_incr:N \l__knot_component_start_int
   \tl_set_eq:Nc \l__knot_tmpa_tl {l__knot_options_strand #1}
-  \spath_map_segment_function:nN {knot strand #1} \knot_save_filament:NN
+  \spath_segments_to_seq:Nv \l__knot_segments_seq {knot strand #1}
+  \seq_map_function:NN \l__knot_segments_seq \knot_save_filament:N
 }
-\cs_new_protected_nopar:Npn \knot_save_filament:NN #1#2
+\cs_new_protected_nopar:Npn \knot_save_filament:N #1
 {
-  \tl_case:NnF #1
+  \tl_set:Nx \l__knot_tmpb_tl {\tl_item:nn {#1} {4}}
+  \tl_case:NnF \l__knot_tmpb_tl
   {
-    \g__spath_moveto_tl
+    \c_spath_moveto_tl
     {
-      \int_compare:nT {\l__knot_component_start_int < \l__knot_filaments_int}
+      \int_compare:nT {\l__knot_component_start_int < \g__knot_filaments_int}
       {
-        \int_set_eq:NN \l__knot_component_start_int \l__knot_filaments_int
+        \int_set_eq:NN \l__knot_component_start_int \g__knot_filaments_int
       }
     }
-    \g__spath_lineto_tl
+    \c_spath_lineto_tl
     {
-      \int_gincr:N \l__knot_filaments_int
-      \spath_clear_new:n {knot filament \int_use:N \l__knot_filaments_int}
-      \spath_put:nnV {knot filament \int_use:N \l__knot_filaments_int} {path} #2
-      \tl_set_eq:cN {l__knot_options_filament \int_use:N \l__knot_filaments_int} \l__knot_tmpa_tl
+      \int_gincr:N \g__knot_filaments_int
+      \tl_clear_new:c {knot filament \int_use:N \g__knot_filaments_int}
+      \tl_set:cn {knot filament \int_use:N \g__knot_filaments_int} {#1}
+
+      \tl_clear_new:c {l__knot_options_filament \int_use:N \g__knot_filaments_int}
+      \tl_set_eq:cN {l__knot_options_filament \int_use:N \g__knot_filaments_int} \l__knot_tmpa_tl
 
-      \tl_clear_new:c {knot previous filament \int_use:N \l__knot_filaments_int}
-      \int_compare:nF {\l__knot_component_start_int == \l__knot_filaments_int}
+      \tl_clear_new:c {knot previous filament \int_use:N \g__knot_filaments_int}
+      \int_compare:nF {\l__knot_component_start_int == \g__knot_filaments_int}
       {
-        \tl_set:cx {knot previous filament \int_use:N \l__knot_filaments_int} {filament \int_eval:n {\l__knot_filaments_int - 1}}
+        \tl_set:cx {knot previous filament \int_use:N \g__knot_filaments_int} {filament \int_eval:n {\g__knot_filaments_int - 1}}
       }
     }
-    \g__spath_curvetoa_tl
+    \c_spath_curvetoa_tl
     {
-      \int_gincr:N \l__knot_filaments_int
-      \spath_clear_new:n {knot filament \int_use:N \l__knot_filaments_int}
-      \spath_put:nnV {knot filament \int_use:N \l__knot_filaments_int} {path} #2
-      \tl_set_eq:cN {l__knot_options_filament \int_use:N \l__knot_filaments_int} \l__knot_tmpa_tl
+      \int_gincr:N \g__knot_filaments_int
+      \tl_clear_new:c {knot filament \int_use:N \g__knot_filaments_int}
+      \tl_set:cn {knot filament \int_use:N \g__knot_filaments_int} {#1}
+      \tl_clear_new:c {l__knot_options_filament \int_use:N \g__knot_filaments_int}
+      \tl_set_eq:cN {l__knot_options_filament \int_use:N \g__knot_filaments_int} \l__knot_tmpa_tl
 
-      \tl_clear_new:c {knot previous filament \int_use:N \l__knot_filaments_int}
-      \int_compare:nF {\l__knot_component_start_int == \l__knot_filaments_int}
+      \tl_clear_new:c {knot previous filament \int_use:N \g__knot_filaments_int}
+      \int_compare:nF {\l__knot_component_start_int == \g__knot_filaments_int}
       {
-        \tl_set:cx {knot previous filament \int_use:N \l__knot_filaments_int} {filament \int_eval:n {\l__knot_filaments_int - 1}}
+        \tl_set:cx {knot previous filament \int_use:N \g__knot_filaments_int} {filament \int_eval:n {\g__knot_filaments_int - 1}}
       }
     }
-    \g__spath_closepath_tl
+    \c_spath_closepath_tl
     {
-      \tl_show:N #2
-      \int_gincr:N \l__knot_filaments_int
-      \spath_clear_new:n {knot filament \int_use:N \l__knot_filaments_int}
-      \tl_clear:N \l_tmpa_tl
-      \tl_put_right:Nx {\tl_item:Nn #2 {1}\tl_item:Nn #2 {2}\tl_item:Nn #2 {3}}
-      \tl_put_right:NV \l_tmpa_tl \g__spath_lineto_tl
-      \tl_put_right:Nx {\tl_item:Nn #2 {5}\tl_item:Nn #2 {6}}
-      \tl_show:N \l_tmpa_tl
-      \spath_put:nnV {knot filament \int_use:N \l__knot_filaments_int} {path} \l_tmpa_tl
-      \tl_set_eq:cN {l__knot_options_filament \int_use:N \l__knot_filaments_int} \l__knot_tmpa_tl
-      \tl_clear_new:c {knot previous filament \int_use:N \l__knot_filaments_int}
-      \int_compare:nF {\l__knot_component_start_int == \l__knot_filaments_int}
+      \int_gincr:N \g__knot_filaments_int
+      \tl_clear_new:c {knot filament \int_use:N \g__knot_filaments_int}
+      \tl_clear:N \l__knot_tmpa_tl
+      \tl_put_right:Nx {\tl_item:nn {#1} {1}\tl_item:nn {#1} {2}\tl_item:nn {#1} {3}}
+      \tl_put_right:NV \l__knot_tmpa_tl \c_spath_lineto_tl
+      \tl_put_right:Nx {\tl_item:nn {#1} {5}\tl_item:nn {#1} {6}}
+
+      \tl_set:cV {knot filament \int_use:N \g__knot_filaments_int} \l__knot_tmpa_tl
+      \tl_set_eq:cN {l__knot_options_filament \int_use:N \g__knot_filaments_int} \l__knot_tmpa_tl
+      \tl_clear_new:c {knot previous filament \int_use:N \g__knot_filaments_int}
+      \int_compare:nF {\l__knot_component_start_int == \g__knot_filaments_int}
       {
-        \tl_set:cx {knot previous filament \int_use:N \l__knot_filaments_int} {filament \int_eval:n {\l__knot_filaments_int - 1}}
+        \tl_set:cx {knot previous filament \int_use:N \g__knot_filaments_int} {filament \int_eval:n {\g__knot_filaments_int - 1}}
       }
-      \tl_set:cx {knot previous filament \int_use:N \l__knot_component_start_int} {filament \int_use:N \l__knot_filaments_int}
+      \tl_set:cx {knot previous filament \int_use:N \l__knot_component_start_int} {filament \int_use:N \g__knot_filaments_int}
     }
   }
   {
@@ -990,7 +1008,7 @@
  }
 }
 %% 
-%% Copyright (C) 2011-2019 by Andrew Stacey <stacey@math.ntnu.no>
+%% Copyright (C) 2011-2019 by Andrew Stacey <loopspace@mathforge.org>
 %% 
 %% This work may be distributed and/or modified under the
 %% conditions of the LaTeX Project Public License (LPPL), either
@@ -1005,13 +1023,16 @@
 %% This work consists of the files  spath3.dtx
 %%                                  calligraphy_doc.tex
 %%                                  knots_doc.tex
+%%                                  spath3.tex
 %% and the derived files            spath3.ins,
 %%                                  spath3_code.pdf,
 %%                                  spath3.sty,
 %%                                  tikzlibrarycalligraphy.code.tex
 %%                                  tikzlibraryknots.code.tex
+%%                                  tikzlibraryspath3.code.tex
 %%                                  calligraphy.pdf
 %%                                  knots.pdf
+%%                                  spath3.pdf
 %%                                  README
 %% 
 %%