c

slowgraph/dgtxt.typ

@@ -0,0 +1,75 @@
+= dgtxt file format
+Human readable file format for directed graphs
+
+== Design goals
+- any valid input to `tsort`, not containing `#`, is always valid dgtxt.
+- removing every occureance of the RegEx `#.*?\n` should produce a valid input to `tsort` (if it doesn't contain cycles of course)
+- easy to generate
+- human readable
+- easy to parse fully
+
+== Concepts
+=== Node
+Has:
+- incoming edges
+- outgoing edges
+- name
+- key-value attributes
+
+=== Edge
+Has:
+- source node
+- destination node
+- key-value attributes
+
+== Syntax
+Note that `{x}` means none or more times.
+
+```ebnf
+ident char = anything - '\n' - '\r' - ' ' - '#';
+ident = ident char, { ident char };
+
+node attribute = '##', {spaces},
+                 ident, {spaces},  (* referred node *)
+                 ident, {spaces},  (* attribute key *)
+                 { not new line }  (* attribute value *)
+               ;
+
+comment = '#', { note new line };
+
+edge attribute = '#:', {spaces}, ident, {spaces}, {not new line} ;
+
+edge = ident, {spaces},  (* source node *)
+       ident, {spaces},  (* destination node *)
+       { {spaces}, edge attribute, {spaces} }
+     ;
+
+element = edge
+        | node attribute
+        | comment
+        ;
+
+
+grammar = { spaces, element, spaces };
+```
+
+== Example
+```
+# comment line (ignored)
+DownloadLinux FlashDrive
+# double hashtass start node attributes:
+## DownloadLinux describtion Attrbiute key/value formats are not standardized her
+FindFlashDrive    FlashDrive   #: cost 200
+                               #: another-attr-key  another attr value (until end of line)
+DownloadDriveFlashSoftware FlashDrive
+FlashDrive ShutdownWindows
+ShutdownWindows  RestartPc
+RestartPc InstallLinux
+```
+
+== Recommendations
+- tools should prefix attribute names with the tool names, unless they think that other tools might adopt that attribute too.
+- tools that modify graphs should preserve all attributes
+- tools should not error on unknown attributes (or invalid attribute values), as they might be valid in a different tool
+- actual comments should have a space after the `#`, for future proofing
+- node attributes be listed directly after node definitions

slowgraph/sgraph-adj.c

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+#define SLOWGRAPH_IMPL
+#include "../slowgraph.h"
+
+static void write_csv_field(char const *s) {
+  char const *y;
+  int quote = 0;
+  for (y = s; *y; y++) {
+    if (*y == '\n' || *y == '"') {
+      quote = 1;
+      break;
+    }
+  }
+
+  if (quote)
+    putchar('"');
+
+  for (; *s; s++) {
+    if (*s == '"')
+      putchar('"');
+    putchar(*s);
+  }
+
+  if (quote)
+    putchar('"');
+}
+
+static void dump_adj_matrix_row(SlowGraph *g, SlowGraphNode *row) {
+  SlowGraphNode *col;
+  write_csv_field(row->name);
+  printf(",");
+  for (col = g->first; col; col = col->next) {
+    if (SlowGraphNode_findConnection(row, col)) {
+      printf("1,");
+    } else {
+      printf("0,");
+    }
+  }
+  printf("\n");
+}
+
+static void dump_adj_matrix(SlowGraph *g) {
+  SlowGraphNode *n;
+  printf(",");
+  for (n = g->first; n; n = n->next) {
+    if (n != g->first)
+      printf(",");
+    write_csv_field(n->name);
+  }
+  printf("\n");
+  for (n = g->first; n; n = n->next) {
+    dump_adj_matrix_row(g, n);
+  }
+}
+
+int main(int argc, char **argv) {
+  SlowGraph graph = {0};
+
+  if (SlowGraph_readDGTXT(&graph, stdin))
+    return 1;
+
+  dump_adj_matrix(&graph);
+  return 0;
+}