Load templates and render objects

Sources/HummingbirdMustache/Template+Parser.swift

@@ -0,0 +1,71 @@
+
+extension HBTemplate {
+    static func parse(_ string: String) throws -> [Token] {
+        var parser = HBParser(string)
+        return try parse(&parser, sectionName: nil)
+    }
+
+    static func parse(_ parser: inout HBParser, sectionName: String?) throws -> [Token] {
+        var tokens: [Token] = []
+        while !parser.reachedEnd() {
+            let text = try parser.read(untilString: "{{", throwOnOverflow: false, skipToEnd: true)
+            tokens.append(.text(text.string))
+            if parser.reachedEnd() {
+                break
+            }
+            switch parser.current() {
+            case "#":
+                parser.unsafeAdvance()
+                let name = try parseSectionName(&parser)
+                let sectionTokens = try parse(&parser, sectionName: name)
+                tokens.append(.section(name, HBTemplate(sectionTokens)))
+
+            case "^":
+                parser.unsafeAdvance()
+                let name = try parseSectionName(&parser)
+                let sectionTokens = try parse(&parser, sectionName: name)
+                tokens.append(.invertedSection(name, HBTemplate(sectionTokens)))
+
+            case "/":
+                parser.unsafeAdvance()
+                let name = try parseSectionName(&parser)
+                guard name == sectionName else {
+                    throw HBMustacheError.sectionCloseNameIncorrect
+                }
+                return tokens
+
+            case "{":
+                parser.unsafeAdvance()
+                let name = try parseSectionName(&parser)
+                guard try parser.read("}") else { throw HBMustacheError.unfinishedSectionName }
+                tokens.append(.variable(name))
+
+            case "!":
+                parser.unsafeAdvance()
+                _ = try parseSection(&parser)
+
+            default:
+                let name = try parseSectionName(&parser)
+                tokens.append(.variable(name))
+            }
+        }
+        // should never get here if reading section
+        guard sectionName == nil else {
+            throw HBMustacheError.expectedSectionEnd
+        }
+        return tokens
+    }
+
+    static func parseSectionName(_ parser: inout HBParser) throws -> String {
+        let text = parser.read(while: sectionNameChars )
+        guard try parser.read("}"), try parser.read("}") else { throw HBMustacheError.unfinishedSectionName }
+        return text.string
+    }
+
+    static func parseSection(_ parser: inout HBParser) throws -> String {
+        let text = try parser.read(untilString: "}}", throwOnOverflow: true, skipToEnd: true)
+        return text.string
+    }
+    
+    private static let sectionNameChars = Set<Unicode.Scalar>("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.")
+}