Revert "Initial checkin of SkSL lexical analyzer generator (not actually in use yet)."

This reverts commit 3de0e496b5215bcf4b26db2d69dc84376dfd68d2.

Reason for revert: Google3 roll failure

Original change's description:
> Initial checkin of SkSL lexical analyzer generator (not actually in use yet).
> 
> Bug: skia:
> Change-Id: I283feb9ac1cef134588204107ea019ce657e37b3
> Reviewed-on: https://skia-review.googlesource.com/42084
> Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

TBR=bsalomon@google.com,ethannicholas@google.com

Change-Id: Ifa9a054aba9baa1e0d17309a2e1838b5d3b0bfec
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/43340
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>

14 files changed, 0 insertions, 1251 deletions

diff --git a/BUILD.gn b/BUILD.gn
index 1c328b0452..4b34a6dca1 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -412,16 +412,6 @@ optional("fontmgr_fuchsia") {
 }
 
 if (skia_compile_processors) {
-  executable("sksllex") {
-    sources = [
-      "src/sksl/lex/Main.cpp",
-      "src/sksl/lex/NFA.cpp",
-      "src/sksl/lex/RegexNode.cpp",
-      "src/sksl/lex/RegexParser.cpp",
-    ]
-    include_dirs = [ "src/sksl/lex" ]
-  }
-
   executable("skslc") {
     defines = [ "SKSL_STANDALONE" ]
     sources = [
diff --git a/src/sksl/lex/DFA.h b/src/sksl/lex/DFA.h
deleted file mode 100644
index 51e85ca2f8..0000000000
--- a/src/sksl/lex/DFA.h
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SKSL_DFA
-#define SKSL_DFA
-
-#include <string>
-#include <vector>
-
-/**
- * Tables representing a deterministic finite automaton for matching regular expressions.
- */
-struct DFA {
-    DFA(std::vector<std::vector<int>> transitions, std::vector<int> accepts)
-    : fTransitions(transitions)
-    , fAccepts(accepts) {}
-
-    static constexpr char END_CHAR = 126;
-
-    // one row per character, one column per state
-    std::vector<std::vector<int>> fTransitions;
-
-    // contains, for each state, the token id we should report when matching ends in that state (-1
-    // for no match)
-    std::vector<int> fAccepts;
-};
-
-#endif
diff --git a/src/sksl/lex/DFAState.h b/src/sksl/lex/DFAState.h
deleted file mode 100644
index b2c89fd4cb..0000000000
--- a/src/sksl/lex/DFAState.h
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SKSL_DFASTATE
-#define SKSL_DFASTATE
-
-struct DFAState {
-    struct Label {
-        std::vector<int> fStates;
-
-        Label(std::vector<int> states)
-        : fStates(std::move(states)) {}
-
-        bool operator==(const Label& other) const {
-            return fStates == other.fStates;
-        }
-
-        bool operator!=(const Label& other) const {
-            return !(*this == other);
-        }
-
-        std::string description() const {
-            std::string result = "<";
-            const char* separator = "";
-            for (int s : fStates) {
-                result += separator;
-                result += std::to_string(s);
-                separator = ", ";
-            }
-            result += ">";
-            return result;
-        }
-    };
-
-    DFAState()
-    : fId(-1)
-    , fLabel({}) {}
-
-    DFAState(int id, Label label)
-    : fId(id)
-    , fLabel(std::move(label)) {}
-
-    DFAState(const DFAState& other) = delete;
-
-    int fId;
-
-    Label fLabel;
-
-    bool fIsScanned = false;
-};
-
-namespace std {
-    template<> struct hash<DFAState::Label> {
-        size_t operator()(const DFAState::Label& s) const {
-            int result = 0;
-            for (int i : s.fStates) {
-                result = result * 101 + i;
-            }
-            return result;
-        }
-    };
-} // namespace
-
-#endif
diff --git a/src/sksl/lex/LexUtil.h b/src/sksl/lex/LexUtil.h
deleted file mode 100644
index d2c462b0ed..0000000000
--- a/src/sksl/lex/LexUtil.h
+++ /dev/null
@@ -1,14 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SKSL_LEXUTIL
-#define SKSL_LEXUTIL
-
-#define ABORT(...) (fprintf(stderr, __VA_ARGS__), abort())
-#define ASSERT(x) (void)((x) || (ABORT("failed assert(%s): %s:%d\n", #x, __FILE__, __LINE__), 0))
-
-#endif
diff --git a/src/sksl/lex/Main.cpp b/src/sksl/lex/Main.cpp
deleted file mode 100644
index a5c7320356..0000000000
--- a/src/sksl/lex/Main.cpp
+++ /dev/null
@@ -1,197 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "NFAtoDFA.h"
-#include "RegexParser.h"
-
-#include <fstream>
-#include <sstream>
-#include <string>
-
-/**
- * Processes a .lex file and produces .h and .cpp files which implement a lexical analyzer. The .lex
- * file is a text file with one token definition per line. Each line is of the form:
- * <TOKEN_NAME> = <pattern>
- * where <pattern> is either a regular expression (e.g [0-9]) or a double-quoted literal string.
- */
-
-static constexpr const char* HEADER =
-    "/*\n"
-    " * Copyright 2017 Google Inc.\n"
-    " *\n"
-    " * Use of this source code is governed by a BSD-style license that can be\n"
-    " * found in the LICENSE file.\n"
-    " */\n"
-    "/*****************************************************************************************\n"
-    " ******************** This file was generated by sksllex. Do not edit. *******************\n"
-    " *****************************************************************************************/\n";
-
-void writeH(const DFA& dfa, const char* lexer, const char* token,
-            const std::vector<std::string>& tokens, const char* hPath) {
-    std::ofstream out(hPath);
-    ASSERT(out.good());
-    out << HEADER;
-    out << "#ifndef SKSL_" << lexer << "\n";
-    out << "#define SKSL_" << lexer << "\n";
-    out << "#include <cstddef>\n";
-    out << "#include <cstdint>\n";
-    out << "namespace SkSL {\n";
-    out << "\n";
-    out << "struct " << token << " {\n";
-    out << "    enum Kind {\n";
-    for (const std::string& t : tokens) {
-        out << "        #undef " << t << "\n";
-        out << "        " << t << ",\n";
-    }
-    out << "    };\n";
-    out << "\n";
-    out << "    " << token << "()\n";
-    out << "    : fKind(Kind::INVALID)\n";
-    out << "    , fOffset(-1)\n";
-    out << "    , fLength(-1) {}\n";
-    out << "\n";
-    out << "    " << token << "(Kind kind, int offset, int length)\n";
-    out << "    : fKind(kind)\n";
-    out << "    , fOffset(offset)\n";
-    out << "    , fLength(length) {}\n";
-    out << "\n";
-    out << "    Kind fKind;\n";
-    out << "    int fOffset;\n";
-    out << "    int fLength;\n";
-    out << "};\n";
-    out << "\n";
-    out << "class " << lexer << " {\n";
-    out << "public:\n";
-    out << "    void start(const char* text, size_t length) {\n";
-    out << "        fText = text;\n";
-    out << "        fLength = length;\n";
-    out << "        fOffset = 0;\n";
-    out << "    }\n";
-    out << "\n";
-    out << "    " << token << " next();\n";
-    out << "\n";
-    out << "private:\n";
-    out << "    const char* fText;\n";
-    out << "    int fLength;\n";
-    out << "    int fOffset;\n";
-    out << "};\n";
-    out << "\n";
-    out << "} // namespace\n";
-    out << "#endif\n";
-}
-
-void writeCPP(const DFA& dfa, const char* lexer, const char* token, const char* include,
-              const char* cppPath) {
-    std::ofstream out(cppPath);
-    ASSERT(out.good());
-    out << HEADER;
-    out << "#include \"" << include << "\"\n";
-    out << "\n";
-    out << "namespace SkSL {\n";
-    out << "\n";
-
-    size_t states = 0;
-    for (const auto& row : dfa.fTransitions) {
-        states = std::max(states, row.size());
-    }
-    out << "static int16_t transitions[" << DFA::END_CHAR + 1 << "][" << states << "] = {\n";
-    for (char c = 0; c <= DFA::END_CHAR; ++c) {
-        out << "    {";
-        for (size_t i = 0; i < states; ++i) {
-            if ((size_t) c < dfa.fTransitions.size() && i < dfa.fTransitions[c].size()) {
-                out << " " << dfa.fTransitions[c][i] << ",";
-            } else {
-                out << " 0,";
-            }
-        }
-        out << " },\n";
-    }
-    out << "};\n";
-    out << "\n";
-
-    out << "static int16_t accepts[" << states << "] = {";
-    for (size_t i = 0; i < states; ++i) {
-        if (i < dfa.fAccepts.size()) {
-            out << " " << dfa.fAccepts[i] << ",";
-        } else {
-            out << " -1,";
-        }
-    }
-    out << " };\n";
-    out << "\n";
-
-    out << token << " " << lexer << "::next() {\n";;
-    out << "    int startOffset = fOffset;\n";
-    out << "    if (startOffset == fLength) {\n";
-    out << "        return " << token << "(" << token << "::END_OF_FILE, startOffset, 0);\n";
-    out << "    }\n";
-    out << "    int offset = startOffset;\n";
-    out << "    int state = 1;\n";
-    out << "    " << token << "::Kind lastAccept = " << token << "::Kind::INVALID;\n";
-    out << "    int lastAcceptEnd = startOffset + 1;\n";
-    out << "    while (offset < fLength) {\n";
-    out << "        state = transitions[(int) fText[offset]][state];\n";
-    out << "        ++offset;\n";
-    out << "        if (!state) {\n";
-    out << "            break;\n";
-    out << "        }\n";
-    out << "        if (accepts[state]) {\n";
-    out << "            lastAccept = (" << token << "::Kind) accepts[state];\n";
-    out << "            lastAcceptEnd = offset;\n";
-    out << "        }\n";
-    out << "    }\n";
-    out << "    fOffset = lastAcceptEnd;\n";
-    out << "    return " << token << "(lastAccept, startOffset, lastAcceptEnd - startOffset);\n";
-    out << "}\n";
-    out << "\n";
-    out << "} // namespace\n";
-}
-
-void process(const char* inPath, const char* lexer, const char* token, const char* hPath,
-             const char* cppPath) {
-    NFA nfa;
-    std::vector<std::string> tokens;
-    tokens.push_back("END_OF_FILE");
-    std::string line;
-    std::ifstream in(inPath);
-    while (std::getline(in, line)) {
-        std::istringstream split(line);
-        std::string name, delimiter, pattern;
-        if (split >> name >> delimiter >> pattern) {
-            ASSERT(split.eof());
-            ASSERT(name != "");
-            ASSERT(delimiter == "=");
-            ASSERT(pattern != "");
-            tokens.push_back(name);
-            if (pattern[0] == '"') {
-                ASSERT(pattern.size() > 2 && pattern[pattern.size() - 1] == '"');
-                RegexNode node = RegexNode(RegexNode::kChar_Kind, pattern[1]);
-                for (size_t i = 2; i < pattern.size() - 1; ++i) {
-                    node = RegexNode(RegexNode::kConcat_Kind, node,
-                                     RegexNode(RegexNode::kChar_Kind, pattern[i]));
-                }
-                nfa.addRegex(node);
-            }
-            else {
-                nfa.addRegex(RegexParser().parse(pattern));
-            }
-        }
-    }
-    NFAtoDFA converter(&nfa);
-    DFA dfa = converter.convert();
-    writeH(dfa, lexer, token, tokens, hPath);
-    writeCPP(dfa, lexer, token, (std::string("SkSL") + lexer + ".h").c_str(), cppPath);
-}
-
-int main(int argc, const char** argv) {
-    if (argc != 6) {
-        printf("usage: sksllex <input.lex> <lexername> <tokenname> <output.h> <output.cpp>\n");
-        exit(1);
-    }
-    process(argv[1], argv[2], argv[3], argv[4], argv[5]);
-    return 0;
-}
diff --git a/src/sksl/lex/NFA.cpp b/src/sksl/lex/NFA.cpp
deleted file mode 100644
index d1eb7497b3..0000000000
--- a/src/sksl/lex/NFA.cpp
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "NFA.h"
-
-int NFA::match(std::string s) const {
-    std::vector<int> states = fStartStates;
-    for (size_t i = 0; i < s.size(); ++i) {
-        std::vector<int> next;
-        for (int id : states) {
-            if (fStates[id].accept(s[i])) {
-                for (int nextId : fStates[id].fNext) {
-                    if (fStates[nextId].fKind != NFAState::kRemapped_Kind) {
-                        next.push_back(nextId);
-                    } else {
-                        next.insert(next.end(), fStates[nextId].fData.begin(),
-                                    fStates[nextId].fData.end());
-                    }
-                }
-            }
-        }
-        if (!next.size()) {
-            return -1;
-        }
-        states = next;
-    }
-    int accept = -1;
-    for (int id : states) {
-        if (fStates[id].fKind == NFAState::kAccept_Kind) {
-            int result = fStates[id].fData[0];
-            if (accept == -1 || result < accept) {
-                accept = result;
-            }
-        }
-    }
-    return accept;
-}
diff --git a/src/sksl/lex/NFA.h b/src/sksl/lex/NFA.h
deleted file mode 100644
index e454d37f2a..0000000000
--- a/src/sksl/lex/NFA.h
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SKSL_NFA
-#define SKSL_NFA
-
-#include "NFAState.h"
-#include "RegexNode.h"
-
-/**
- * A nondeterministic finite automaton for matching regular expressions. The NFA is initialized with
- * a number of regular expressions, and then matches a string against all of them simultaneously.
- */
-struct NFA {
-    /**
-     * Adds a new regular expression to the set of expressions matched by this automaton, returning
-     * its index.
-     */
-    int addRegex(const RegexNode& regex) {
-        std::vector<int> accept;
-        // we reserve token 0 for END_OF_FILE, so this starts at 1
-        accept.push_back(this->addState(NFAState(++fRegexCount)));
-        std::vector<int> startStates = regex.createStates(this, accept);
-        fStartStates.insert(fStartStates.end(), startStates.begin(), startStates.end());
-        return fStartStates.size() - 1;
-    }
-
-    /**
-     * Adds a new state to the NFA, returning its index.
-     */
-    int addState(NFAState s) {
-        fStates.push_back(std::move(s));
-        return fStates.size() - 1;
-    }
-
-    /**
-     * Matches a string against all of the regexes added to this NFA. Returns the index of the first
-     * (in addRegex order) matching expression, or -1 if no match. This is relatively slow and used
-     * only for debugging purposes; the NFA should be converted to a DFA before actual use.
-     */
-    int match(std::string s) const;
-
-    int fRegexCount = 0;
-
-    std::vector<NFAState> fStates;
-
-    std::vector<int> fStartStates;
-};
-
-#endif
diff --git a/src/sksl/lex/NFAState.h b/src/sksl/lex/NFAState.h
deleted file mode 100644
index 5923507571..0000000000
--- a/src/sksl/lex/NFAState.h
+++ /dev/null
@@ -1,150 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SKSL_NFASTATE
-#define SKSL_NFASTATE
-
-#include <string>
-#include <vector>
-
-#include "LexUtil.h"
-
-struct NFAState {
-    enum Kind {
-        // represents an accept state - if the NFA ends up in this state, we have successfully
-        // matched the token indicated by fData[0]
-        kAccept_Kind,
-        // matches the single character fChar
-        kChar_Kind,
-        // the regex '.'; matches any char but '\n'
-        kDot_Kind,
-        // a state which serves as a placeholder for the states indicated in fData. When we
-        // transition to this state, we instead transition to all of the fData states.
-        kRemapped_Kind,
-        // contains a list of true/false values in fData. fData[c] tells us whether we accept the
-        // character c.
-        kTable_Kind
-    };
-
-    NFAState(Kind kind, std::vector<int> next)
-    : fKind(kind)
-    , fNext(std::move(next)) {}
-
-    NFAState(char c, std::vector<int> next)
-    : fKind(kChar_Kind)
-    , fChar(c)
-    , fNext(std::move(next)) {}
-
-    NFAState(std::vector<int> states)
-    : fKind(kRemapped_Kind)
-    , fData(std::move(states)) {}
-
-    NFAState(bool inverse, std::vector<bool> accepts, std::vector<int> next)
-    : fKind(kTable_Kind)
-    , fInverse(inverse)
-    , fNext(std::move(next)) {
-        for (bool b : accepts) {
-            fData.push_back(b);
-        }
-    }
-
-    NFAState(int token)
-    : fKind(kAccept_Kind) {
-        fData.push_back(token);
-    }
-
-    bool accept(char c) const {
-        switch (fKind) {
-            case kAccept_Kind:
-                return false;
-            case kChar_Kind:
-                return c == fChar;
-            case kDot_Kind:
-                return c != '\n';
-            case kTable_Kind: {
-                bool value;
-                if ((size_t) c < fData.size()) {
-                    value = fData[c];
-                } else {
-                    value = false;
-                }
-                return value != fInverse;
-            }
-            default:
-                ABORT("unreachable");
-        }
-    }
-
-    std::string description() const {
-        switch (fKind) {
-            case kAccept_Kind:
-                return "Accept(" + std::to_string(fData[0]) + ")";
-            case kChar_Kind: {
-                std::string result = "Char('" + std::string(1, fChar) + "'";
-                for (int v : fNext) {
-                    result += ", ";
-                    result += std::to_string(v);
-                }
-                result += ")";
-                return result;
-            }
-            case kDot_Kind: {
-                std::string result = "Dot(";
-                const char* separator = "";
-                for (int v : fNext) {
-                    result += separator;
-                    result += std::to_string(v);
-                    separator = ", ";
-                }
-                result += ")";
-                return result;
-            }
-            case kRemapped_Kind: {
-                std::string result = "Remapped(";
-                const char* separator = "";
-                for (int v : fData) {
-                    result += separator;
-                    result += std::to_string(v);
-                    separator = ", ";
-                }
-                result += ")";
-                return result;
-            }
-            case kTable_Kind: {
-                std::string result = std::string("Table(") + (fInverse ? "true" : "false") + ", [";
-                const char* separator = "";
-                for (int v : fData) {
-                    result += separator;
-                    result += v ? "true" : "false";
-                    separator = ", ";
-                }
-                result += "]";
-                for (int n : fNext) {
-                    result += ", ";
-                    result += std::to_string(n);
-                }
-                result += ")";
-                return result;
-            }
-            default:
-                ABORT("unreachable");
-        }
-    }
-
-    Kind fKind;
-
-    char fChar = 0;
-
-    bool fInverse = false;
-
-    std::vector<int> fData;
-
-    // states we transition to upon a succesful match from this state
-    std::vector<int> fNext;
-};
-
-#endif
diff --git a/src/sksl/lex/NFAtoDFA.h b/src/sksl/lex/NFAtoDFA.h
deleted file mode 100644
index 214c6d12d6..0000000000
--- a/src/sksl/lex/NFAtoDFA.h
+++ /dev/null
@@ -1,130 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "DFA.h"
-#include "DFAState.h"
-#include "NFA.h"
-#include "NFAState.h"
-
-#include <algorithm>
-#include <climits>
-#include <memory>
-#include <unordered_map>
-#include <vector>
-
-/**
- * Converts a nondeterministic finite automaton to a deterministic finite automaton. Since NFAs and
- * DFAs differ only in that an NFA allows multiple states at the same time, we can find each
- * possible combination of simultaneous NFA states and give this combination a label. These labelled
- * nodes are our DFA nodes, since we can only be in one such unique set of NFA states at a time.
- *
- * As an NFA can end up in multiple accept states at the same time (for instance, the token "while"
- * is valid for both WHILE and IDENTIFIER), we disambiguate by preferring the first matching regex
- * (in terms of the order in which they were added to the NFA).
- */
-class NFAtoDFA {
-public:
-    NFAtoDFA(NFA* nfa)
-    : fNFA(*nfa) {}
-
-    /**
-     * Returns a DFA created from the NFA.
-     */
-    DFA convert() {
-        // create state 0, the "reject" state
-        getState(DFAState::Label({}));
-        // create a state representing being in all of the NFA's start states at once
-        std::vector<int> startStates = fNFA.fStartStates;
-        std::sort(startStates.begin(), startStates.end());
-        // this becomes state 1, our start state
-        DFAState* start = getState(DFAState::Label(startStates));
-        this->scanState(start);
-
-        int stateCount = 0;
-        for (const auto& row : fTransitions) {
-            stateCount = std::max(stateCount, (int) row.size());
-        }
-        return DFA(fTransitions, fAccepts);
-    }
-
-private:
-    /**
-     * Returns an existing state with the given label, or creates a new one and returns it.
-     */
-    DFAState* getState(DFAState::Label label) {
-        auto found = fStates.find(label);
-        if (found == fStates.end()) {
-            int id = fStates.size();
-            fStates[label] = std::unique_ptr<DFAState>(new DFAState(id, label));
-            return fStates[label].get();
-        }
-        return found->second.get();
-    }
-
-    void add(int nfaState, std::vector<int>* states) {
-        NFAState state = fNFA.fStates[nfaState];
-        if (state.fKind == NFAState::kRemapped_Kind) {
-            for (int next : state.fData) {
-                this->add(next, states);
-            }
-        } else {
-            for (int state : *states) {
-                if (nfaState == state) {
-                    return;
-                }
-            }
-            states->push_back(nfaState);
-        }
-    }
-
-    void addTransition(char c, int start, int next) {
-        while (fTransitions.size() <= (size_t) c) {
-            fTransitions.push_back(std::vector<int>());
-        }
-        std::vector<int>& row = fTransitions[c];
-        while (row.size() <= (size_t) start) {
-            row.push_back(-1);
-        }
-        row[start] = next;
-    }
-
-    void scanState(DFAState* state) {
-        state->fIsScanned = true;
-        for (char c = 9; c <= DFA::END_CHAR; ++c) {
-            std::vector<int> next;
-            int bestAccept = INT_MAX;
-            for (int idx : state->fLabel.fStates) {
-                const NFAState& nfaState = fNFA.fStates[idx];
-                if (nfaState.accept(c)) {
-                    for (int nextState : nfaState.fNext) {
-                        if (fNFA.fStates[nextState].fKind == NFAState::kAccept_Kind) {
-                            bestAccept = std::min(bestAccept, fNFA.fStates[nextState].fData[0]);
-                        }
-                        this->add(nextState, &next);
-                    }
-                }
-            }
-            std::sort(next.begin(), next.end());
-            DFAState* nextState = this->getState(DFAState::Label(next));
-            this->addTransition(c, state->fId, nextState->fId);
-            if (bestAccept != INT_MAX) {
-                while (fAccepts.size() <= (size_t) nextState->fId) {
-                    fAccepts.push_back(-1);
-                }
-                fAccepts[nextState->fId] = bestAccept;
-            }
-            if (!nextState->fIsScanned) {
-                this->scanState(nextState);
-            }
-        }
-    }
-
-    const NFA& fNFA;
-    std::unordered_map<DFAState::Label, std::unique_ptr<DFAState>> fStates;
-    std::vector<std::vector<int>> fTransitions;
-    std::vector<int> fAccepts;
-};
diff --git a/src/sksl/lex/RegexNode.cpp b/src/sksl/lex/RegexNode.cpp
deleted file mode 100644
index 8915c60c44..0000000000
--- a/src/sksl/lex/RegexNode.cpp
+++ /dev/null
@@ -1,117 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "RegexNode.h"
-
-#include "NFA.h"
-
-std::vector<int> RegexNode::createStates(NFA* nfa, const std::vector<int>& accept) const {
-    std::vector<int> result;
-    switch (fKind) {
-        case kChar_Kind:
-            result.push_back(nfa->addState(NFAState(fPayload.fChar, accept)));
-            break;
-        case kCharset_Kind: {
-            std::vector<bool> chars;
-            for (const RegexNode& child : fChildren) {
-                if (child.fKind == kChar_Kind) {
-                    while (chars.size() <= (size_t) child.fPayload.fChar) {
-                        chars.push_back(false);
-                    }
-                    chars[child.fPayload.fChar] = true;
-                } else {
-                    ASSERT(child.fKind == kRange_Kind);
-                    while (chars.size() <= (size_t) child.fChildren[1].fPayload.fChar) {
-                        chars.push_back(false);
-                    }
-                    for (char c = child.fChildren[0].fPayload.fChar;
-                         c <= child.fChildren[1].fPayload.fChar;
-                         ++c) {
-                        chars[c] = true;
-                    }
-                }
-            }
-            result.push_back(nfa->addState(NFAState(fPayload.fBool, chars, accept)));
-            break;
-        }
-        case kConcat_Kind: {
-            std::vector<int> right = fChildren[1].createStates(nfa, accept);
-            result = fChildren[0].createStates(nfa, right);
-            break;
-        }
-        case kDot_Kind:
-            result.push_back(nfa->addState(NFAState(NFAState::kDot_Kind, accept)));
-            break;
-        case kOr_Kind: {
-            std::vector<int> states = fChildren[0].createStates(nfa, accept);
-            result.insert(result.end(), states.begin(), states.end());
-            states = fChildren[1].createStates(nfa, accept);
-            result.insert(result.end(), states.begin(), states.end());
-            break;
-        }
-        case kPlus_Kind: {
-            std::vector<int> next = accept;
-            std::vector<int> placeholder;
-            int id = nfa->addState(NFAState(placeholder));
-            next.push_back(id);
-            result = fChildren[0].createStates(nfa, next);
-            nfa->fStates[id] = NFAState(result);
-            break;
-        }
-        case kQuestion_Kind:
-            result = fChildren[0].createStates(nfa, accept);
-            result.insert(result.end(), accept.begin(), accept.end());
-            break;
-        case kRange_Kind:
-            ABORT("unreachable");
-        case kStar_Kind: {
-            std::vector<int> next = accept;
-            std::vector<int> placeholder;
-            int id = nfa->addState(NFAState(placeholder));
-            next.push_back(id);
-            result = fChildren[0].createStates(nfa, next);
-            result.insert(result.end(), accept.begin(), accept.end());
-            nfa->fStates[id] = NFAState(result);
-            break;
-        }
-    }
-    return result;
-}
-
-std::string RegexNode::description() const {
-    switch (fKind) {
-        case kChar_Kind:
-            return std::string(1, fPayload.fChar);
-        case kCharset_Kind: {
-            std::string result("[");
-            if (fPayload.fBool) {
-                result += "^";
-            }
-            for (const RegexNode& c : fChildren) {
-                result += c.description();
-            }
-            result += "]";
-            return result;
-        }
-        case kConcat_Kind:
-            return fChildren[0].description() + fChildren[1].description();
-        case kDot_Kind:
-            return ".";
-        case kOr_Kind:
-            return "(" + fChildren[0].description() + "|" + fChildren[1].description() + ")";
-        case kPlus_Kind:
-            return fChildren[0].description() + "+";
-        case kQuestion_Kind:
-            return fChildren[0].description() + "?";
-        case kRange_Kind:
-            return fChildren[0].description() + "-" + fChildren[1].description();
-        case kStar_Kind:
-            return fChildren[0].description() + "*";
-        default:
-            return "<" + std::to_string(fKind) + ">";
-    }
-}
diff --git a/src/sksl/lex/RegexNode.h b/src/sksl/lex/RegexNode.h
deleted file mode 100644
index e3aa65b3d1..0000000000
--- a/src/sksl/lex/RegexNode.h
+++ /dev/null
@@ -1,78 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SKSL_REGEXNODE
-#define SKSL_REGEXNODE
-
-#include <string>
-#include <vector>
-
-struct NFA;
-
-/**
- * Represents a node in the parse tree of a regular expression.
- */
-struct RegexNode {
-    enum Kind {
-        kChar_Kind,
-        kCharset_Kind,
-        kConcat_Kind,
-        kDot_Kind,
-        kOr_Kind,
-        kPlus_Kind,
-        kRange_Kind,
-        kQuestion_Kind,
-        kStar_Kind
-    };
-
-    RegexNode(Kind kind)
-    : fKind(kind) {}
-
-    RegexNode(Kind kind, char payload)
-    : fKind(kind) {
-        fPayload.fChar = payload;
-    }
-
-    RegexNode(Kind kind, const char* children)
-    : fKind(kind) {
-        fPayload.fBool = false;
-        while (*children != '\0') {
-            fChildren.emplace_back(kChar_Kind, *children);
-            ++children;
-        }
-    }
-
-    RegexNode(Kind kind, RegexNode child)
-    : fKind(kind) {
-        fChildren.push_back(std::move(child));
-    }
-
-    RegexNode(Kind kind, RegexNode child1, RegexNode child2)
-    : fKind(kind) {
-        fChildren.push_back(std::move(child1));
-        fChildren.push_back(std::move(child2));
-    }
-
-    /**
-     * Creates NFA states for this node, with a successful match against this node resulting in a
-     * transition to all of the states in the accept vector.
-     */
-    std::vector<int> createStates(NFA* nfa, const std::vector<int>& accept) const;
-
-    std::string description() const;
-
-    Kind fKind;
-
-    union Payload {
-        char fChar;
-        bool fBool;
-    } fPayload;
-
-    std::vector<RegexNode> fChildren;
-};
-
-#endif
diff --git a/src/sksl/lex/RegexParser.cpp b/src/sksl/lex/RegexParser.cpp
deleted file mode 100644
index 154df159db..0000000000
--- a/src/sksl/lex/RegexParser.cpp
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "RegexParser.h"
-
-#include "LexUtil.h"
-
-RegexNode RegexParser::parse(std::string source) {
-    fSource = source;
-    fIndex = 0;
-    ASSERT(fStack.size() == 0);
-    this->regex();
-    ASSERT(fStack.size() == 1);
-    ASSERT(fIndex == source.size());
-    return this->pop();
-}
-
-char RegexParser::peek() {
-    if (fIndex >= fSource.size()) {
-        return END;
-    }
-    return fSource[fIndex];
-}
-
-void RegexParser::expect(char c) {
-    if (this->peek() != c) {
-        printf("expected '%c' at index %d, but found '%c'", c, (int) fIndex, this->peek());
-        exit(1);
-    }
-    ++fIndex;
-}
-
-RegexNode RegexParser::pop() {
-    RegexNode result = fStack.top();
-    fStack.pop();
-    return result;
-}
-
-void RegexParser::term() {
-    switch (this->peek()) {
-        case '(': this->group();  break;
-        case '[': this->set();    break;
-        case '.': this->dot();    break;
-        default: this->literal();
-    }
-}
-
-void RegexParser::quantifiedTerm() {
-    this->term();
-    switch (this->peek()) {
-        case '*': fStack.push(RegexNode(RegexNode::kStar_Kind,     this->pop())); ++fIndex; break;
-        case '+': fStack.push(RegexNode(RegexNode::kPlus_Kind,     this->pop())); ++fIndex; break;
-        case '?': fStack.push(RegexNode(RegexNode::kQuestion_Kind, this->pop())); ++fIndex; break;
-        default:  break;
-    }
-}
-
-void RegexParser::sequence() {
-    this->quantifiedTerm();
-    for (;;) {
-        switch (this->peek()) {
-            case END: // fall through
-            case '|': // fall through
-            case ')': return;
-            default:
-                this->sequence();
-                RegexNode right = this->pop();
-                RegexNode left = this->pop();
-                fStack.emplace(RegexNode::kConcat_Kind, std::move(left), std::move(right));
-        }
-    }
-}
-
-RegexNode RegexParser::escapeSequence(char c) {
-    switch (c) {
-        case 'n': return RegexNode(RegexNode::kChar_Kind, '\n');
-        case 'r': return RegexNode(RegexNode::kChar_Kind, '\r');
-        case 't': return RegexNode(RegexNode::kChar_Kind, '\t');
-        case 's': return RegexNode(RegexNode::kCharset_Kind, " \t\n\r");
-        default:  return RegexNode(RegexNode::kChar_Kind, c);
-    }
-}
-
-void RegexParser::literal() {
-    char c = this->peek();
-    if (c == '\\') {
-        ++fIndex;
-        fStack.push(this->escapeSequence(peek()));
-        ++fIndex;
-    }
-    else {
-        fStack.push(RegexNode(RegexNode::kChar_Kind, c));
-        ++fIndex;
-    }
-}
-
-void RegexParser::dot() {
-    this->expect('.');
-    fStack.push(RegexNode(RegexNode::kDot_Kind));
-}
-
-void RegexParser::group() {
-    this->expect('(');
-    this->regex();
-    this->expect(')');
-}
-
-void RegexParser::setItem() {
-    this->literal();
-    if (this->peek() == '-') {
-        ++fIndex;
-        if (peek() == ']') {
-            fStack.push(RegexNode(RegexNode::kChar_Kind, '-'));
-        }
-        else {
-            literal();
-            RegexNode end = this->pop();
-            ASSERT(end.fKind == RegexNode::kChar_Kind);
-            RegexNode start = this->pop();
-            ASSERT(start.fKind == RegexNode::kChar_Kind);
-            fStack.push(RegexNode(RegexNode::kRange_Kind, std::move(start), std::move(end)));
-        }
-    }
-}
-
-void RegexParser::set() {
-    expect('[');
-    size_t depth = fStack.size();
-    RegexNode set(RegexNode::kCharset_Kind);
-    if (this->peek() == '^') {
-        ++fIndex;
-        set.fPayload.fBool = true;
-    }
-    else {
-        set.fPayload.fBool = false;
-    }
-    for (;;) {
-        switch (this->peek()) {
-            case ']':
-                ++fIndex;
-                while (fStack.size() > depth) {
-                    set.fChildren.push_back(this->pop());
-                }
-                fStack.push(std::move(set));
-                return;
-            case END:
-                printf("unterminated character set\n");
-                exit(1);
-            default:
-                this->setItem();
-        }
-    }
-}
-
-void RegexParser::regex() {
-    this->sequence();
-    switch (this->peek()) {
-        case '|': {
-            ++fIndex;
-            this->regex();
-            RegexNode right = this->pop();
-            RegexNode left = this->pop();
-            fStack.push(RegexNode(RegexNode::kOr_Kind, left, right));
-            break;
-        }
-        case END: // fall through
-        case ')':
-            return;
-        default:
-            ASSERT(false);
-    }
-}
diff --git a/src/sksl/lex/RegexParser.h b/src/sksl/lex/RegexParser.h
deleted file mode 100644
index 7de546fc17..0000000000
--- a/src/sksl/lex/RegexParser.h
+++ /dev/null
@@ -1,89 +0,0 @@
-/*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SKSL_REGEXPARSER
-#define SKSL_REGEXPARSER
-
-#include "RegexNode.h"
-
-#include <stack>
-#include <string>
-
-/**
- * Turns a simple regular expression into a parse tree. The regular expression syntax supports only
- * the basic quantifiers ('*', '+', and '?'), alternation ('|'), character sets ('[a-z]'), and
- * groups ('()').
- */
-class RegexParser {
-public:
-    RegexNode parse(std::string source);
-
-private:
-    static constexpr char END = '\0';
-
-    char peek();
-
-    void expect(char c);
-
-    RegexNode pop();
-
-    /**
-     * Matches a char literal, parenthesized group, character set, or dot ('.').
-     */
-    void term();
-
-    /**
-     * Matches a term followed by an optional quantifier ('*', '+', or '?').
-     */
-    void quantifiedTerm();
-
-    /**
-     * Matches a sequence of quantifiedTerms.
-     */
-    void sequence();
-
-    /**
-     * Returns a node representing the given escape character (e.g. escapeSequence('n') returns a
-     * node which matches a newline character).
-     */
-    RegexNode escapeSequence(char c);
-
-    /**
-     * Matches a literal character or escape sequence.
-     */
-    void literal();
-
-    /**
-     * Matches a dot ('.').
-     */
-    void dot();
-
-    /**
-     * Matches a parenthesized group.
-     */
-    void group();
-
-    /**
-     * Matches a literal character, escape sequence, or character range from a character set.
-     */
-    void setItem();
-
-    /**
-     * Matches a character set.
-     */
-    void set();
-
-    void regex();
-
-    std::string fSource;
-
-    size_t fIndex;
-
-    std::stack<RegexNode> fStack;
-};
-
-#endif
diff --git a/src/sksl/lex/sksl.lex b/src/sksl/lex/sksl.lex
deleted file mode 100644
index ada5e248de..0000000000
--- a/src/sksl/lex/sksl.lex
+++ /dev/null
@@ -1,95 +0,0 @@
-FLOAT_LITERAL  = [0-9]*\.[0-9]+([eE][+-]?[0-9]+)?|[0-9]+\.[0-9]*([eE][+-]?[0-9]+)?|[0-9]+([eE][+-]?[0-9]+)
-INT_LITERAL    = [0-9]+|0x[0-9a-fA-F]+
-TRUE_LITERAL   = "true"
-FALSE_LITERAL  = "false"
-IF             = "if"
-STATIC_IF      = "@if"
-ELSE           = "else"
-FOR            = "for"
-WHILE          = "while"
-DO             = "do"
-SWITCH         = "switch"
-STATIC_SWITCH  = "@switch"
-CASE           = "case"
-DEFAULT        = "default"
-BREAK          = "break"
-CONTINUE       = "continue"
-DISCARD        = "discard"
-RETURN         = "return"
-IN             = "in"
-OUT            = "out"
-INOUT          = "inout"
-UNIFORM        = "uniform"
-CONST          = "const"
-LOWP           = "lowp"
-MEDIUMP        = "mediump"
-HIGHP          = "highp"
-FLAT           = "flat"
-NOPERSPECTIVE  = "noperspective"
-READONLY       = "readonly"
-WRITEONLY      = "writeonly"
-COHERENT       = "coherent"
-VOLATILE       = "volatile"
-RESTRICT       = "restrict"
-BUFFER         = "buffer"
-HASSIDEEFFECTS = "sk_has_side_effects"
-STRUCT         = "struct"
-LAYOUT         = "layout"
-PRECISION      = "precision"
-IDENTIFIER     = [a-zA-Z_$]([0-9]|[a-zA-Z_$])*
-DIRECTIVE      = #[a-zA-Z_$]([0-9]|[a-zA-Z_$])*
-SECTION        = @[a-zA-Z_$]([0-9]|[a-zA-Z_$])*
-LPAREN         = "("
-RPAREN         = ")"
-LBRACE         = "{"
-RBRACE         = "}"
-LBRACKET       = "["
-RBRACKET       = "]"
-DOT            = "."
-COMMA          = ","
-PLUSPLUS       = "++"
-MINUSMINUS     = "--"
-PLUS           = "+"
-MINUS          = "-"
-STAR           = "*"
-SLASH          = "/"
-PERCENT        = "%"
-SHL            = "<<"
-SHR            = ">>"
-BITWISEOR      = "|"
-BITWISEXOR     = "^"
-BITWISEAND     = "&"
-BITWISENOT     = "~"
-LOGICALOR      = "||"
-LOGICALXOR     = "^^"
-LOGICALAND     = "&&"
-LOGICALNOT     = "!"
-QUESTION       = "?"
-COLON          = ":"
-EQ             = "="
-EQEQ           = "=="
-NEQ            = "!="
-GT             = ">"
-LT             = "<"
-GTEQ           = ">="
-LTEQ           = "<="
-PLUSEQ         = "+="
-MINUSEQ        = "-="
-STAREQ         = "*="
-SLASHEQ        = "/="
-PERCENTEQ      = "%="
-SHLEQ          = "<<="
-SHREQ          = ">>="
-BITWISEOREQ    = "|="
-BITWISEXOREQ   = "^="
-BITWISEANDEQ   = "&="
-LOGICALOREQ    = "||="
-LOGICALXOREQ   = "^^="
-LOGICALANDEQ   = "&&="
-SEMICOLON      = ";"
-ARROW          = "->"
-COLONCOLON     = "::"
-WHITESPACE     = \s+
-LINE_COMMENT   = //.*
-BLOCK_COMMENT  = /\*([^*]|\*[^/])*\*/
-INVALID        = .
\ No newline at end of file