Merge pull request #68 from soasme/dot

[Example] Write a DOT parser using Peppa PEG.

README.md

@@ -184,6 +184,7 @@ The outputs are stored on `build/docs`.
 * Write a Mustache Parser using Peppa PEG: [mustache.h](examples/mustache.h).
 * Write a JSON Parser using Peppa PEG: [json.h](examples/json.h).
 * Write a Calculator Parser using Peppa PEG: [calc.h](examples/calc.h), [calc.c](examples/calc.c).
+* Write a [Dot](https://graphviz.org/doc/info/lang.html) parser using Peppa PEG: [dot.h](examples/dot.h).
 
 Made with ❤️  by [Ju](https://github.com/soasme).
 

examples/dot.h

@@ -0,0 +1,155 @@
+/*
+ * Peppa PEG -  Ultra lightweight PEG Parser in ANSI C.
+ *
+ * MIT License
+ *
+ * Copyright (c) 2021 Ju
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Example: Write a DOT Parser using Peppa PEG.
+ *
+ * https://graphviz.org/doc/info/lang.html
+ *
+*/
+
+# ifndef P4_LANG_DOT_H
+# define P4_LANG_DOT_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include "../peppapeg.h"
+
+typedef enum P4_DotRule {
+    P4_DotRuleEntry = 1,
+    P4_DotRuleGraph,
+    P4_DotRuleID,
+    P4_DotRuleIdentifier,
+    P4_DotRuleNumber,
+    P4_DotRuleString,
+    P4_DotRuleNodeID,
+    P4_DotRuleNodeStmt,
+    P4_DotRulePort,
+    P4_DotRuleCompassPt,
+    P4_DotRuleAttribute,
+    P4_DotRuleAList,
+    P4_DotRuleAttrList,
+    P4_DotRuleAttrStmt,
+    P4_DotRuleKeywordGraph,
+    P4_DotRuleKeywordNode,
+    P4_DotRuleKeywordEdge,
+    P4_DotRuleStatement,
+    P4_DotRuleWhitespace,
+    P4_DotRuleDirectedEdgeOP,
+    P4_DotRuleUndirectedEdgeOP,
+    P4_DotRuleEdgeOP,
+    P4_DotRuleKeywordSubgraph,
+    P4_DotRuleSubgraph,
+    P4_DotRuleStatements,
+    P4_DotRuleEdgeStmt,
+    P4_DotRuleKeywordDigraph,
+    P4_DotRuleStrict,
+    P4_DotRuleComment,
+    P4_DotRuleMacroComment,
+    P4_DotRuleCComment,
+    P4_DotRuleBlockComment,
+    P4_DotRuleHtmlString,
+} P4_DotRule;
+
+P4_Grammar* P4_CreateDotGrammar() {
+    return P4_LoadGrammar(
+        "@lifted\n"
+        "entry = &. graph+ !.;\n"
+
+        "graph = keyword_strict? (keyword_graph / keyword_digraph) ID? \"{\" stmts \"}\";\n"
+
+        "@squashed\n"
+        "ID = identifier / number / html_string / string;\n"
+
+        "@squashed @tight\n"
+        "identifier = ([a-z]/[A-Z]/\"_\") ([a-z]/[A-Z]/[0-9]/\"_\")*;\n"
+
+        "@squashed @tight\n"
+        "number = \"-\"? ((\".\" [0-9]+) / [0-9]+ (\".\" [0-9]*)?);\n"
+
+        "@squashed @tight\n"
+        "string = \"\\\"\" (!\"\\\"\" . / \"\\\\\\\"\")+ \"\\\"\";\n"
+
+        "@nonterminal\n"
+        "node_id = ID port?;\n"
+
+        "node_stmt = node_id attr_list?;\n"
+
+        "port = \":\" compass_pt / \":\" ID (\":\" compass_pt)?;\n"
+
+        "compass_pt = \"ne\" / \"nw\" / \"n\" / \"se\" / \"sw\" / \"s\" / \"e\" / \"w\" / \"c\" / \"_\";\n"
+
+        "attribute = ID \"=\" ID;\n"
+
+        "@lifted\n"
+        "a_list = attribute ((\";\" / \",\") attribute)*;\n"
+
+        "attr_list = (\"[\" a_list \"]\")+;\n"
+
+        "attr_stmt = (keyword_graph / keyword_node / keyword_edge) attr_list;\n"
+        "keyword_graph = \"graph\";\n"
+        "keyword_node= \"node\";\n"
+        "keyword_edge= \"edge\";\n"
+
+        "@lifted\n"
+        "stmt = edge_stmt / subgraph / attr_stmt / attribute / node_stmt;\n"
+
+        "@spaced @lifted\n"
+        "ws = \" \" / \"\\t\" / \"\\n\" / \"\\r\";"
+
+        "directed = \"->\";"
+        "undirected = \"--\";"
+
+        "@lifted\n"
+        "edgeop = directed / undirected;\n"
+
+        "keyword_subgraph = \"subgraph\";\n"
+
+        "subgraph = (keyword_subgraph ID?)? \"{\" stmts? \"}\";\n"
+        "stmts = stmt (\";\"? stmt)*;\n"
+
+        "edge_stmt = (node_id / subgraph) (edgeop (node_id / subgraph))+ attr_list?;"
+
+        "keyword_digraph = \"digraph\";\n"
+        "keyword_strict = \"strict\";\n"
+
+        "@spaced @squashed @lifted\n"
+        "comment = macro_comment / c_comment / block_comment;\n"
+        "macro_comment = \"#\" (!\"\\n\" .)* \"\\n\"?;\n"
+        "c_comment = \"//\" (!\"\\n\" .)* \"\\n\"?;\n"
+        "block_comment = \"/*\" (!\"*/\" .)* \"*/\";\n"
+
+        "@squashed\n"
+        "html_string = \"<\" ((!(\"<\" / \">\") .)+/ html_string)* \">\";\n"
+    );
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+# endif

tests/CMakeLists.txt

@@ -19,6 +19,7 @@ set(
     test_example_mustache
     test_example_json
     test_example_calc
+    test_example_dot
 )
 
 option(ENABLE_VALGRIND "Enable vagrind memory leak report." OFF)