style(eval): move in its own package

5 files changed, 548 insertions, 0 deletions

diff --git a/src/eval/Element.zig b/src/eval/Element.zig
new file mode 100644
index 0000000..e017bc5
--- /dev/null
+++ b/src/eval/Element.zig
@@ -0,0 +1,136 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+pub const HTML = @import("html/Element.zig");
+pub const Paragraph = struct {
+    const paragraph = @import("paragraph.zig");
+    pub const Block = paragraph.Block;
+    pub const Bold = paragraph.Bold;
+    pub const Code = paragraph.Code;
+    pub const Italic = paragraph.Italic;
+    pub const Link = paragraph.Link;
+};
+pub const Title = @import("Title.zig");
+
+const Element = @This();
+
+vtable: struct {
+    deinit: *const fn (*anyopaque, Allocator) void,
+    html: *const fn (*anyopaque, Allocator) HTML.Error!HTML,
+},
+ptr: *anyopaque,
+
+pub fn renderHTML(self: Element, alloc: Allocator) HTML.Error![]const u8 {
+    var el = try self.vtable.html(self.ptr, alloc);
+    defer el.deinit();
+    return el.render(alloc);
+}
+
+pub fn deinit(self: Element, alloc: Allocator) void {
+    self.vtable.deinit(self.ptr, alloc);
+}
+
+pub fn html(self: Element, alloc: Allocator) HTML.Error!HTML {
+    return self.vtable.html(self.ptr, alloc);
+}
+
+pub const Empty = struct {
+    content: std.ArrayList(Element),
+
+    const Self = @This();
+
+    pub fn init(alloc: Allocator) !*Self {
+        const v = try alloc.create(Self);
+        v.* = .{ .content = try .initCapacity(alloc, 2) };
+        return v;
+    }
+
+    pub fn element(self: *Self) Element {
+        return .{ .ptr = self, .vtable = .{ .deinit = destroy, .html = Self.html } };
+    }
+
+    pub fn deinit(self: *Self, alloc: Allocator) void {
+        destroy(self, alloc);
+    }
+
+    fn destroy(context: *anyopaque, alloc: Allocator) void {
+        const self: *Self = @ptrCast(@alignCast(context));
+        for (self.content.items) |it| it.deinit(alloc);
+        self.content.deinit(alloc);
+        alloc.destroy(self);
+    }
+
+    fn html(context: *anyopaque, alloc: Allocator) HTML.Error!HTML {
+        const self: *Self = @ptrCast(@alignCast(context));
+        var el = HTML.initEmpty(alloc);
+        errdefer el.deinit();
+        for (self.content.items) |it| try el.appendContent(try it.html(alloc));
+        return el;
+    }
+};
+
+pub const Literal = struct {
+    content: []const u8,
+
+    const Self = @This();
+
+    pub fn init(alloc: Allocator, content: []const u8) !*Self {
+        const v = try alloc.create(Self);
+        v.* = .{ .content = content };
+        return v;
+    }
+
+    pub fn element(self: *Self) Element {
+        return .{ .ptr = self, .vtable = .{ .deinit = destroy, .html = Self.html } };
+    }
+
+    pub fn deinit(self: *Self, alloc: Allocator) void {
+        destroy(self, alloc);
+    }
+
+    fn destroy(context: *anyopaque, alloc: Allocator) void {
+        const self: *Self = @ptrCast(@alignCast(context));
+        alloc.destroy(self);
+    }
+
+    fn html(context: *anyopaque, alloc: Allocator) HTML.Error!HTML {
+        const self: *Self = @ptrCast(@alignCast(context));
+        return HTML.initLitEscaped(alloc, self.content);
+    }
+};
+
+pub fn Simple(comptime tag: []const u8) type {
+    return struct {
+        content: std.ArrayList(Element),
+
+        const Self = @This();
+
+        pub fn init(alloc: Allocator) !*Self {
+            const v = try alloc.create(Self);
+            v.* = .{ .content = try .initCapacity(alloc, 2) };
+            return v;
+        }
+
+        pub fn element(self: *Self) Element {
+            return .{ .ptr = self, .vtable = .{ .deinit = destroy, .html = Self.html } };
+        }
+
+        pub fn deinit(self: *Self, alloc: Allocator) void {
+            destroy(self, alloc);
+        }
+
+        fn destroy(context: *anyopaque, alloc: Allocator) void {
+            var self: *Self = @ptrCast(@alignCast(context));
+            for (self.content.items) |it| it.deinit(alloc);
+            self.content.deinit(alloc);
+            alloc.destroy(self);
+        }
+
+        fn html(context: *anyopaque, alloc: Allocator) HTML.Error!HTML {
+            const self: *Self = @ptrCast(@alignCast(context));
+            var el = try HTML.init(alloc, .content, tag);
+            errdefer el.deinit();
+            for (self.content.items) |it| try el.appendContent(try it.html(alloc));
+            return el;
+        }
+    };
+}
diff --git a/src/eval/Title.zig b/src/eval/Title.zig
new file mode 100644
index 0000000..56524ad
--- /dev/null
+++ b/src/eval/Title.zig
@@ -0,0 +1,45 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const HTML = Parent.HTML;
+const Parent = @import("Element.zig");
+
+level: u3,
+content: Parent,
+
+const Self = @This();
+
+pub fn init(alloc: Allocator, level: u3, content: Parent) !*Self {
+    const v = try alloc.create(Self);
+    v.* = .{ .level = level, .content = content };
+    return v;
+}
+
+pub fn element(self: *Self) Parent {
+    return .{ .ptr = self, .vtable = .{ .deinit = destroy, .html = html } };
+}
+
+pub fn deinit(self: *Self, alloc: Allocator) void {
+    self.element().deinit(alloc);
+}
+
+fn destroy(context: *anyopaque, alloc: Allocator) void {
+    var self: *Self = @ptrCast(@alignCast(context));
+    self.content.deinit(alloc);
+    alloc.destroy(self);
+}
+
+fn html(context: *anyopaque, alloc: Allocator) HTML.Error!HTML {
+    const self: *Self = @ptrCast(@alignCast(context));
+    var el = try HTML.init(alloc, .content, switch (self.level) {
+        1 => "h1",
+        2 => "h2",
+        3 => "h3",
+        4 => "h4",
+        5 => "h5",
+        6 => "h6",
+        else => unreachable,
+        });
+    errdefer el.deinit();
+    try el.appendContent(try self.content.html(alloc));
+    return el;
+}
diff --git a/src/eval/html/Element.zig b/src/eval/html/Element.zig
new file mode 100644
index 0000000..87fd876
--- /dev/null
+++ b/src/eval/html/Element.zig
@@ -0,0 +1,241 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const eql = std.mem.eql;
+const html = @import("html.zig");
+
+pub const Kind = enum {
+    void,
+    content,
+    literal,
+};
+
+pub const Error = html.Error || Allocator.Error;
+
+const Self = @This();
+
+kind: Kind,
+arena: std.heap.ArenaAllocator,
+tag: ?[]const u8 = null,
+attributes: std.StringArrayHashMap([]const u8),
+class_list: std.BufSet,
+content: std.ArrayList(Self) = .empty,
+literal: ?[]const u8 = null,
+
+/// Init a new Element with the given kind.
+/// The tag will never be escaped.
+/// It always duplicates strings.
+pub fn init(alloc: Allocator, knd: Kind, tag: []const u8) Error!Self {
+    var v = Self{
+        .kind = knd,
+        .arena = .init(alloc),
+        .attributes = .init(alloc),
+        .class_list = .init(alloc),
+    };
+    var a = v.arena.allocator();
+    v.tag = try a.dupe(u8, tag);
+    return v;
+}
+
+pub fn initEmpty(alloc: Allocator) Self {
+    return .{
+        .kind = .content,
+        .arena = .init(alloc),
+        .attributes = .init(alloc),
+        .class_list = .init(alloc),
+    };
+}
+
+/// Init a new literal element.
+/// The literal content will never be escaped, see initLitEscaped if you want to escape it.
+/// It always duplicates strings.
+pub fn initLit(alloc: Allocator, literal: []const u8) Error!Self {
+    var v = Self{
+        .kind = .literal,
+        .arena = .init(alloc),
+        .attributes = .init(alloc),
+        .class_list = .init(alloc),
+    };
+    var a = v.arena.allocator();
+    v.literal = try a.dupe(u8, literal);
+    return v;
+}
+
+/// Init a new literal element that is escaped.
+/// The literal content will be escaped, see initLit if you don't want this behavior.
+/// It always duplicates strings.
+pub fn initLitEscaped(alloc: Allocator, literal: []const u8) Error!Self {
+    const escaped = try html.escape(alloc, literal);
+    defer alloc.free(escaped);
+    return .initLit(alloc, escaped);
+}
+
+pub fn deinit(self: *Self) void {
+    self.attributes.deinit();
+    self.class_list.deinit();
+    for (self.content.items) |it| {
+        var v = it;
+        v.deinit();
+    }
+    self.content.deinit(self.arena.allocator());
+    self.arena.deinit();
+}
+
+pub fn render(self: *Self, alloc: Allocator) Error![]const u8 {
+    const attr = try self.renderAttribute(alloc);
+    defer if (attr) |it| alloc.free(it);
+    var acc = try std.ArrayList(u8).initCapacity(alloc, self.content.items.len + if (self.literal) |it| it.len else 0);
+    errdefer acc.deinit(alloc);
+    if (self.tag) |tag| {
+        try acc.append(alloc, '<');
+        try acc.appendSlice(alloc, tag);
+        if (attr) |it| try acc.appendSlice(alloc, it);
+        try acc.append(alloc, '>');
+    }
+    switch (self.kind) {
+        .void => return acc.toOwnedSlice(alloc),
+        .content => {
+            for (self.content.items) |it| {
+                var v = it;
+                const sub = try v.render(alloc);
+                defer alloc.free(sub);
+                try acc.appendSlice(alloc, sub);
+            }
+        },
+        .literal => try acc.appendSlice(alloc, self.literal.?),
+    }
+    if (self.tag) |tag| {
+        try acc.appendSlice(alloc, "</");
+        try acc.appendSlice(alloc, tag);
+        try acc.append(alloc, '>');
+    }
+    return acc.toOwnedSlice(alloc);
+}
+
+fn renderAttribute(self: *Self, alloc: Allocator) Error!?[]const u8 {
+    const class = try self.renderClass(alloc);
+    defer if (class) |it| alloc.free(it);
+    if (class) |it| try self.setAttribute("class", it);
+    var iter = self.attributes.iterator();
+    if (iter.len == 0) return null;
+    var acc = try std.ArrayList(u8).initCapacity(alloc, iter.len);
+    errdefer acc.deinit(alloc);
+    try acc.append(alloc, ' ');
+    var i: usize = 0;
+    while (iter.next()) |it| : (i += 1) {
+        try acc.appendSlice(alloc, it.key_ptr.*);
+        try acc.appendSlice(alloc, "=\"");
+        const escape = try html.escape(alloc, it.value_ptr.*);
+        defer alloc.free(escape);
+        try acc.appendSlice(alloc, escape);
+        try acc.append(alloc, '"');
+        if (i < iter.len - 1) try acc.append(alloc, ' ');
+    }
+    return try acc.toOwnedSlice(alloc);
+}
+
+fn renderClass(self: *const Self, alloc: Allocator) Error!?[]const u8 {
+    var iter = self.class_list.iterator();
+    if (iter.len == 0) return null;
+    const n = self.class_list.count();
+    var acc = try std.ArrayList(u8).initCapacity(alloc, n);
+    errdefer acc.deinit(alloc);
+    var i: usize = 0;
+    while (iter.next()) |it| : (i += 1) {
+        try acc.appendSlice(alloc, it.*);
+        if (i < n - 1) try acc.append(alloc, ' ');
+    }
+    return try acc.toOwnedSlice(alloc);
+}
+
+pub fn setAttribute(self: *Self, k: []const u8, v: []const u8) Error!void {
+    var alloc = self.arena.allocator();
+    try self.attributes.put(try alloc.dupe(u8, k), try alloc.dupe(u8, v));
+}
+
+pub fn removeAttribute(self: *Self, k: []const u8) void {
+    _ = self.attributes.orderedRemove(k);
+}
+
+pub fn hasAttribute(self: *Self, k: []const u8) bool {
+    return self.attributes.contains(k);
+}
+
+pub fn appendClass(self: *Self, v: []const u8) Error!void {
+    var alloc = self.arena.allocator();
+    try self.class_list.insert(try alloc.dupe(u8, v));
+}
+
+pub fn hasClass(self: *Self, v: []const u8) bool {
+    return self.class_list.contains(v);
+}
+
+pub fn removeClass(self: *Self, v: []const u8) void {
+    self.class_list.remove(v);
+}
+
+pub fn appendContent(self: *Self, content: Self) Error!void {
+    const alloc = self.arena.allocator();
+    return self.content.append(alloc, content);
+}
+
+pub fn initImg(alloc: Allocator, src: []const u8, alt: []const u8) Error!Self {
+    var el = try init(alloc, .void, "img");
+    try el.setAttribute("src", src);
+    try el.setAttribute("alt", alt);
+    return el;
+}
+
+pub fn initContent(alloc: Allocator, tag: []const u8, content: []Self) Error!Self {
+    var el = try init(alloc, .content, tag);
+    for (content) |it| try el.appendContent(it);
+    return el;
+}
+
+fn doTest(alloc: Allocator, el: *Self, exp: []const u8) !void {
+    const got = try el.render(alloc);
+    defer alloc.free(got);
+    std.testing.expect(eql(u8, got, exp)) catch |err| {
+        std.debug.print("{s}\n", .{got});
+        return err;
+    };
+}
+
+test "void element" {
+    const alloc = std.testing.allocator;
+
+    var br = try init(alloc, .void, "br");
+    defer br.deinit();
+
+    try doTest(alloc, &br, "<br>");
+
+    var img = try init(alloc, .void, "img");
+    defer img.deinit();
+    try img.setAttribute("src", "foo");
+    try img.setAttribute("alt", "bar");
+
+    try doTest(alloc, &img, "<img src=\"foo\" alt=\"bar\">");
+
+    var img2 = try initImg(alloc, "foo", "bar");
+    defer img2.deinit();
+    try doTest(alloc, &img2, "<img src=\"foo\" alt=\"bar\">");
+}
+
+test "content element" {
+    const alloc = std.testing.allocator;
+
+    var p = try init(alloc, .content, "p");
+
+    var content = try initLit(alloc, "hello world");
+    try p.appendContent(content);
+
+    try doTest(alloc, &content, "hello world");
+    try doTest(alloc, &p, "<p>hello world</p>");
+
+    var div = try init(alloc, .content, "div");
+    defer div.deinit();
+    try div.appendClass("foo-bar");
+    try div.appendContent(p);
+    try div.appendContent(try initImg(alloc, "example.org", "example"));
+
+    try doTest(alloc, &div, "<div class=\"foo-bar\"><p>hello world</p><img src=\"example.org\" alt=\"example\"></div>");
+}
diff --git a/src/eval/html/html.zig b/src/eval/html/html.zig
new file mode 100644
index 0000000..064ebb1
--- /dev/null
+++ b/src/eval/html/html.zig
@@ -0,0 +1,47 @@
+const std = @import("std");
+const eql = std.mem.eql;
+
+pub const Error = error{InvalidUtf8} || std.mem.Allocator.Error;
+
+pub fn escape(alloc: std.mem.Allocator, v: []const u8) Error![]const u8 {
+    var acc = try std.ArrayList(u8).initCapacity(alloc, v.len);
+    errdefer acc.deinit(alloc);
+    const view = try std.unicode.Utf8View.init(v);
+    var iter = view.iterator();
+    while (iter.nextCodepointSlice()) |rune| {
+        if (eql(u8, rune, "&")) {
+            try acc.appendSlice(alloc, "&amp;");
+        } else if (eql(u8, rune, "'")) {
+            try acc.appendSlice(alloc, "&#39;");
+        } else if (eql(u8, rune, "<")) {
+            try acc.appendSlice(alloc, "&lt;");
+        } else if (eql(u8, rune, ">")) {
+            try acc.appendSlice(alloc, "&gt;");
+        } else if (eql(u8, rune, "\"")) {
+            try acc.appendSlice(alloc, "&#34;");
+        } else {
+            try acc.appendSlice(alloc, rune);
+        }
+    }
+    return acc.toOwnedSlice(alloc);
+}
+
+fn doTest(alloc: std.mem.Allocator, el: []const u8, exp: []const u8) !void {
+    const got = try escape(alloc, el);
+    defer alloc.free(got);
+    std.testing.expect(eql(u8, got, exp)) catch |err| {
+        std.debug.print("{s}\n", .{got});
+        return err;
+    };
+}
+
+test "escaping html" {
+    const alloc = std.testing.allocator;
+
+    try doTest(alloc, "hello world", "hello world");
+    try doTest(alloc, "hello&world", "hello&amp;world");
+    try doTest(alloc, "hello'world", "hello&#39;world");
+    try doTest(alloc, "hello<world", "hello&lt;world");
+    try doTest(alloc, "hello>world", "hello&gt;world");
+    try doTest(alloc, "hello\"world", "hello&#34;world");
+}
diff --git a/src/eval/paragraph.zig b/src/eval/paragraph.zig
new file mode 100644
index 0000000..e56b7ff
--- /dev/null
+++ b/src/eval/paragraph.zig
@@ -0,0 +1,79 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const HTML = Element.HTML;
+const Element = @import("Element.zig");
+
+pub const Block = Element.Simple("p");
+
+pub const Bold = Element.Simple("b");
+pub const Italic = Element.Simple("em");
+pub const Code = Element.Simple("code");
+
+
+pub const Link = struct {
+    link: []const u8,
+    content: Element,
+    target: ?[]const u8 = null,
+
+    const Self = @This();
+
+    pub fn init(alloc: Allocator, content: Element, link: []const u8) !*Self {
+        const v = try alloc.create(Self);
+        v.* = .{
+            .content = content,
+            .link = link,
+        };
+        return v;
+    }
+
+    pub fn element(self: *Self) Element {
+        return .{ .ptr = self, .vtable = .{ .deinit = destroy, .html = html } };
+    }
+
+    pub fn deinit(self: *Self, alloc: Allocator) void {
+        destroy(self, alloc);
+    }
+
+    fn destroy(context: *anyopaque, alloc: Allocator) void {
+        var self: *Self = @ptrCast(@alignCast(context));
+        self.content.deinit(alloc);
+        alloc.destroy(self);
+    }
+
+    fn html(context: *anyopaque, alloc: Allocator) HTML.Error!HTML {
+        const self: *Self = @ptrCast(@alignCast(context));
+        var el = try HTML.init(alloc, .content, "a");
+        errdefer el.deinit();
+        try el.appendContent(try self.content.html(alloc));
+        try el.setAttribute("href", self.link);
+        if (self.target) |target| try el.setAttribute("target", target);
+        return el;
+    }
+};
+
+fn doTest(alloc: Allocator, el: Element, exp: []const u8) !void {
+    const got = try el.renderHTML(alloc);
+    defer alloc.free(got);
+    std.testing.expect(std.mem.eql(u8, got, exp)) catch |err| {
+        std.debug.print("{s}\n", .{got});
+        return err;
+    };
+}
+
+test "paragraph" {
+    const alloc = std.testing.allocator;
+
+    const lit = (try Element.Literal.init(alloc, "hello world")).element();
+    try doTest(alloc, lit, "hello world");
+
+    var p = try Block.init(alloc);
+    try p.content.append(alloc, lit);
+    defer p.deinit(alloc);
+    try doTest(alloc, p.element(), "<p>hello world</p>");
+
+    const link = (try Link.init(alloc, (try Element.Literal.init(alloc, "foo")).element(), "example.org")).element();
+    try doTest(alloc, link, "<a href=\"example.org\">foo</a>");
+
+    try p.content.append(alloc, link);
+    try doTest(alloc, p.element(), "<p>hello world<a href=\"example.org\">foo</a></p>");
+}