[Patch V2] Expression spec: update format to support flexible Pcd format

[Yonghong Zhu <yonghong.zhu@intel.com>]

V2: update EBNF for Array format.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Kevin W Shaw <kevin.w.shaw@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
---
 2_expression_overview.md |  3 +++
 3_expression_format.md   | 50 +++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/2_expression_overview.md b/2_expression_overview.md
index 34ceb97..c29a632 100644
--- a/2_expression_overview.md
+++ b/2_expression_overview.md
@@ -100,5 +100,8 @@ directives section do not apply.
 12. Logical operators require operands that are type scalar.
 
 13. For the Conditional Operator, the first operand must be scalar, while the
     second and third operands must have the same type (i.e., both being scalar,
     both being integers, or both being string literals).
+
+14. Array format like "{0x10, 0x20}" can't be a operand of any operator except
+    Relational and equality operators.
diff --git a/3_expression_format.md b/3_expression_format.md
index 50b94c4..1f90fc9 100644
--- a/3_expression_format.md
+++ b/3_expression_format.md
@@ -93,10 +93,21 @@ GRACEFULLY._
 <HexNumber>             ::= <Base16>
 <Base16>                ::= <HexPrefix> [<HexDigit>]+
 <HexDigit>              ::= (a-fA-F0-9)
 <HexPrefix>             ::= {"0x"} {"0X"}
 <GuidValue>             ::= {<RformatGuid>} {<CformatGuid>}
+<UINT8>                 ::= <HexPrefix> (\x0 - \xFF)
+<UINT16>                ::= <HexPrefix> (\x0 - \xFFFF)
+<UINT32>                ::= <HexPrefix> (\x0 - \xFFFFFFFF)
+<UINT64>                ::= <HexPrefix> (\x0 - \xFFFFFFFFFFFFFFFF)
+<ShortNum>              ::= (0-255)
+<IntNum>                ::= (0-65535)
+<LongNum>               ::= (0-4294967295)
+<LongLongNum>           ::= (0-18446744073709551615)
+<GuidStr>               ::= "GUID(" <GuidVal> ")"
+<GuidVal>               ::= {<DblQuote> <RformatGuid> <DblQuote>}
+                            {<CformatGuid>} {<CName>}
 Rhex2                   ::= [<HexDigit>] <HexDigit>
 Rhex4                   ::= [<HexDigit>] [<HexDigit>] Rhex2
 Rhex8                   ::= [<HexDigit>] [<HexDigit>] [<HexDigit>] [<HexDigit>] Rhex4
 <RformatGuid>           ::= Rghex8 "-" Rghex4 "-" Rghex4 "-" Rghex4 "-" Rghex12
 Rghex2                  ::= <HexDigit> <HexDigit>
@@ -111,19 +122,42 @@ Rghex12                 ::= <HexDigit> <HexDigit> <HexDigit> <HexDigit> Rghex8
 <CformatGuid>           ::= "{" [<TSP>]* <Hex32> <CSP> <Hex16> <CSP> <Part2>
 <Part2>                 ::= <Hex16> <CSP> "{" [<TSP>]* <Byte> <CSP> <Part3>
 <Part3>                 ::= <Byte> <CSP> <Byte> <CSP> <Byte> <CSP> <Part4>
 <Part4>                 ::= <Byte> <CSP> <Byte> <CSP> <Byte> <CSP> <Part5>
 <Part5>                 ::= <Byte> [<TSP>]* "}" [<TSP>]* "}"
-<Array>                 ::= {<EmptyArray>} {<Array>}
+<Array>                 ::= {<EmptyArray>} {<NonEmptyArray>}
 <EmptyArray>            ::= "{" <TSP>* "}"
-<ByteArray>             ::= "{" <TSP>* <Byte> [<CSP> <Byte>]* "}"
+<NonEmptyArray>         ::= "{" <TSP>* [<Lable>] <ArrayVal> 
+                             [<CSP> [<Lable>] <ArrayVal>]* "}"
+<ArrayVal>              ::= {<Num8Array>} {<GuidStr>} {<DevicePath>}
+<DevicePath>            ::= "DEVICE_PATH(" <DevicePathStr> ")"
+<DevicePathStr>         ::= A double quoted string that follow the device path
+                            as string format defined in UEFI Specification 2.6
+                            Section 9.6
+<Lable>                 ::= "LABEL(" <CName> ")"
+<Offset>                ::= "OFFSET_OF(" <CName> ")"
 <StringLiteral>         ::= {<QuotedString>} {"L" <QuotedString>}
+                            {<SglQuotedString>} {"L" <SglQuotedString>}
 <DblQuote>              ::= 0x22
+<SglQuote>              ::= 0x27
 <QuotedString>          ::= <DblQuote> [<CCHAR>]* <DblQuote>
+<SglQuotedString>       ::= <SglQuote> [<CCHAR>]* <SglQuote>
 <CCHAR>                 ::= {<SingleChars>} {<EscapeCharSeq>}
-<SingleChars>           ::= {0x20} {0x21} {(0x23 - 0x5B)} {(0x5D - 0x7E)}
-<EscapeCharSeq>         ::= "\" {"n"} {"r"} {"t"} {"f"} {"b"} {"0"} {"\"} {<DblQuote>}
+<SingleChars>           ::= {0x21} {(0x23 - 0x26)} {(0x28 - 0x5B)}
+                            {(0x5D - 0x7E)} {<EscapeSequence>}
+<EscapeCharSeq>         ::= "\" {"n"} {"r"} {"t"} {"f"} {"b"} {"0"} {"\"}
+                            {<DblQuote>} {<SglQuote>}
+<NonNumType>            ::= {<TrueFalse>} {<StringLiteral>} {<Offset>} {<UintMac>}
+<Num8Array>             ::= {<NonNumType>} {<ShortNum>} {<UINT8>}
+<Num16Array>            ::= {<NonNumType>} {<IntNum>} {<UINT16>}
+<Num32Array>            ::= {<NonNumType>} {<LongNum>} {<UINT32>}
+<Num64Array>            ::= {<NonNumType>} {<LongLongNum>} {<UINT64>}
+<UintMac>               ::= {<Uint8Mac>} {<Uint16Mac>} {<Uint32Mac>} {<Uint64Mac>}
+<Uint8Mac>              ::= "UINT8(" <Num8Array> ")"
+<Uint16Mac>             ::= "UINT16(" <Num16Array> ")"
+<Uint32Mac>             ::= "UINT32(" <Num32Array> ")"
+<Uint64Mac>             ::= "UINT64(" <Num64Array> ")"
 <PostFixExpression>     ::= {<PrimaryExpression>} {<PcdName>}
 <PcdName>               ::= <CName> "." <CName>
 <UnaryExpression>       ::= {<PostFixExpression>} {<UnaryOp> <UnaryExpression>}
 <UnaryOp>               ::= {<IntegerOps>} {<ScalarOps>}
 <IntegerOps>            ::= {"+"} {"-"} {"~"}
@@ -187,13 +221,19 @@ gUefiCpuPkgTokenSpaceGuid.PcdCpuLocalApicBaseAddress | !gCrownBayTokenSpaceGuid.
 
 This is the value of the MACRO assigned in a DEFINE statement.
 
 **Expressions**
 
-If the "|" character is used in an expression, the expression must be
+If the "|" or "||"character is used in an expression, the expression must be
 encapsulated by parenthesis.
 
+**OFFSET_OF()**
+
+LABEL() macro in byte arrays to tag the byte offset of a location in a byte
+array. OFFSET_OF() macro in byte arrays that returns the byte offset of a
+LABEL() declared in a byte array.
+
 ## 3.2 Conditional Directive Expressions
 
 Conditional directive statements are defined in the EDK II Platform Description
 (DSC) File and Flash Definition (FDF) File. The following EBNF describes the
 format for expressions used in conditional directives. The format is based on
-- 
2.6.1.windows.1