Reorganized the project as multi-maven module

Updated README
Added language module with grammar
Split the code into common and chapter01 modules.
Removed a number of utility classes that were imported from AA.
Added github workflow file.

5 files changed, 305 insertions, 0 deletions

diff --git a/language/.gitignore b/language/.gitignore
new file mode 100644
index 00000000..58314a2c
--- /dev/null
+++ b/language/.gitignore
@@ -0,0 +1,28 @@
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+target/*
+
+.idea
+*.iml
\ No newline at end of file
diff --git a/language/README.md b/language/README.md
new file mode 100644
index 00000000..09593ab5
--- /dev/null
+++ b/language/README.md
@@ -0,0 +1,6 @@
+# Simple Demo Language
+
+The language is a small subset of the C language.
+
+The grammar of the language is not yet finalized, but for the current definition,
+please look at [grammar](src/main/antlr4/com/seaofnodes/simple/antlr/SimpleLanguage.g4).
\ No newline at end of file
diff --git a/language/examples/all-features.lang b/language/examples/all-features.lang
new file mode 100644
index 00000000..132e4b9c
--- /dev/null
+++ b/language/examples/all-features.lang
@@ -0,0 +1,21 @@
+int i;
+int j;
+
+i = 0;
+j = 100;
+while ( 1 )
+{
+    i = i + 1;
+    j = j - 1;
+    if (i >= j)
+        break;
+}
+
+if (1)
+    i = i + 5;
+else if (2)
+    i = i - 1;
+else
+{
+    j = 0;
+}
\ No newline at end of file
diff --git a/language/pom.xml b/language/pom.xml
new file mode 100644
index 00000000..7d748aa1
--- /dev/null
+++ b/language/pom.xml
@@ -0,0 +1,80 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.seaofnodes</groupId>
+        <artifactId>simple</artifactId>
+        <version>1.0</version>
+    </parent>
+	<artifactId>language-grammar</artifactId>
+	<packaging>jar</packaging>
+	<name>SeaOfNodes Demo Simple Language Grammar</name>
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.target>17</maven.compiler.target>
+		<maven.compiler.source>17</maven.compiler.source>
+		<antlr4test-maven-plugin.version>1.22</antlr4test-maven-plugin.version>
+		<antlr.version>4.11.1</antlr.version>
+		<antlr4test-maven-plugin.version>1.21</antlr4test-maven-plugin.version>
+		<junit.version>4.13.2</junit.version>
+	</properties>
+	<dependencies>
+		<dependency>
+			<groupId>org.antlr</groupId>
+			<artifactId>antlr4-runtime</artifactId>
+			<version>${antlr.version}</version>
+			<type>jar</type>
+			<scope>compile</scope>
+		</dependency>
+	</dependencies>
+	<build>
+		<pluginManagement>
+			<plugins>
+				<plugin>
+					<groupId>org.apache.maven.plugins</groupId>
+					<artifactId>maven-compiler-plugin</artifactId>
+					<version>3.10.1</version>
+				</plugin>
+			</plugins>
+		</pluginManagement>
+		<plugins>
+			<plugin>
+				<groupId>org.antlr</groupId>
+				<artifactId>antlr4-maven-plugin</artifactId>
+				<version>${antlr.version}</version>
+				<configuration>
+					<visitor>true</visitor>
+					<listener>true</listener>
+				</configuration>
+				<executions>
+					<execution>
+						<phase>generate-sources</phase>
+						<goals>
+							<goal>antlr4</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+			<plugin>
+				<groupId>com.khubla.antlr</groupId>
+				<artifactId>antlr4test-maven-plugin</artifactId>
+				<version>${antlr4test-maven-plugin.version}</version>
+				<configuration>
+					<verbose>false</verbose>
+					<showTree>false</showTree>
+					<entryPoint>program</entryPoint>
+					<grammarName>SimpleLanguage</grammarName>
+					<packageName>com.seaofnodes.simple.antlr</packageName>
+					<exampleFiles>examples/</exampleFiles>
+				</configuration>
+				<executions>
+					<execution>
+						<goals>
+							<goal>test</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+</project>
diff --git a/language/src/main/antlr4/com/seaofnodes/simple/antlr/SimpleLanguage.g4 b/language/src/main/antlr4/com/seaofnodes/simple/antlr/SimpleLanguage.g4
new file mode 100644
index 00000000..6779e5a2
--- /dev/null
+++ b/language/src/main/antlr4/com/seaofnodes/simple/antlr/SimpleLanguage.g4
@@ -0,0 +1,170 @@
+grammar SimpleLanguage;
+
+program
+    : declaration* statement+ EOF
+    ;
+
+declaration
+    : type IDENTIFIER ';'
+    ;
+
+type
+    : 'int'
+    ;
+
+statement
+    : 'if' '(' expression ')' statement
+    | 'if' '(' expression ')' statement 'else' statement
+    | 'while' '(' expression ')' statement
+    | IDENTIFIER '=' expression ';'
+    | '{' declaration* statement+ '}'
+    | 'break' ';'
+    ;
+
+expression
+    : primaryExpression                                             # PrimaryExpression_
+    | ('-' | '!') expression                                        # UnaryExpression
+    | expression ('*' | '/' ) expression                            # ArithmeticOrLogicalExpression
+    | expression ('+' | '-') expression                             # ArithmeticOrLogicalExpression
+    | expression ('==' | '!='| '>'| '<'| '>='| '<=') expression     # ComparisonExpression
+    | expression '&&' expression                                    # BooleanExpression
+    | expression '||' expression                                    # BooleanExpression
+    ;
+
+primaryExpression
+    :
+    | INTEGER_LITERAL
+    | IDENTIFIER
+    | '(' expression ')'
+    ;
+
+///////////////////////////////////////////////////////////////////
+
+IDENTIFIER
+    :   IDENTIFIER_NONDIGIT
+        (   IDENTIFIER_NONDIGIT
+        |   DEC_DIGIT
+        )*
+    ;
+
+fragment
+IDENTIFIER_NONDIGIT
+    :   NON_DIGIT
+    |   UNIVERSAL_CHARACTER_NAME
+    ;
+
+fragment
+NON_DIGIT
+    :   [a-zA-Z_]
+    ;
+
+
+fragment
+UNIVERSAL_CHARACTER_NAME
+    :   '\\u' HEX_QUAD
+    |   '\\U' HEX_QUAD HEX_QUAD
+    ;
+
+fragment
+HEX_QUAD
+    :   HEX_DIGIT HEX_DIGIT HEX_DIGIT HEX_DIGIT
+    ;
+
+// tokens char and string
+CHAR_LITERAL
+   : '\''
+   (
+      ~['\\\n\r\t]
+      | QUOTE_ESCAPE
+      | ASCII_ESCAPE
+      | UNICODE_ESCAPE
+   ) '\''
+   ;
+
+STRING_LITERAL
+   : '"'
+   (
+      ~["]
+      | QUOTE_ESCAPE
+      | ASCII_ESCAPE
+      | UNICODE_ESCAPE
+      | ESC_NEWLINE
+   )* '"'
+   ;
+RAW_STRING_LITERAL: 'r' RAW_STRING_CONTENT;
+fragment RAW_STRING_CONTENT: '#' RAW_STRING_CONTENT '#' | '"' .*? '"';
+BYTE_LITERAL: 'b\'' (. | QUOTE_ESCAPE | BYTE_ESCAPE) '\'';
+
+BYTE_STRING_LITERAL: 'b"' (~["] | QUOTE_ESCAPE | BYTE_ESCAPE)* '"';
+RAW_BYTE_STRING_LITERAL: 'br' RAW_STRING_CONTENT;
+fragment ASCII_ESCAPE: '\\x' OCT_DIGIT HEX_DIGIT | COMMON_ESCAPE;
+fragment BYTE_ESCAPE: '\\x' HEX_DIGIT HEX_DIGIT | COMMON_ESCAPE;
+fragment COMMON_ESCAPE: '\\' [nrt\\0];
+fragment UNICODE_ESCAPE
+   : '\\u{' HEX_DIGIT HEX_DIGIT? HEX_DIGIT? HEX_DIGIT? HEX_DIGIT? HEX_DIGIT? '}'
+   ;
+fragment QUOTE_ESCAPE: '\\' ['"];
+fragment ESC_NEWLINE: '\\' '\n';
+
+// number
+INTEGER_LITERAL
+   :
+   (
+      DEC_LITERAL
+      | BIN_LITERAL
+      | OCT_LITERAL
+      | HEX_LITERAL
+   ) INTEGER_SUFFIX?
+   ;
+DEC_LITERAL: DEC_DIGIT (DEC_DIGIT | '_')*;
+HEX_LITERAL: '0x' '_'* HEX_DIGIT (HEX_DIGIT | '_')*;
+OCT_LITERAL: '0o' '_'* OCT_DIGIT (OCT_DIGIT | '_')*;
+BIN_LITERAL: '0b' '_'* [01] [01_]*;
+FLOAT_LITERAL
+   : DEC_LITERAL
+   (
+      '.' DEC_LITERAL
+   )? FLOAT_EXPONENT? FLOAT_SUFFIX?
+   ;
+
+fragment INTEGER_SUFFIX
+   : 'u8'
+   | 'u16'
+   | 'u32'
+   | 'u64'
+   | 'u128'
+   | 'usize'
+   | 'i8'
+   | 'i16'
+   | 'i32'
+   | 'i64'
+   | 'i128'
+   | 'isize'
+   ;
+
+fragment FLOAT_SUFFIX: 'f32' | 'f64';
+fragment FLOAT_EXPONENT: [eE] [+-]? '_'* DEC_LITERAL;
+fragment OCT_DIGIT: [0-7];
+fragment DEC_DIGIT: [0-9];
+fragment HEX_DIGIT: [0-9a-fA-F];
+
+
+WHITESPACE
+    :   [ \t]+
+        -> skip
+    ;
+
+NEWLINE
+    :   (   '\r' '\n'?
+        |   '\n'
+        )
+        -> skip
+    ;
+
+LINE_COMMENT
+    :   '//' ~[\r\n]*
+        -> skip
+    ;
+
+
+ANY: . ;
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